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- USA
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Ships within 48 hours · Estimated delivery Jul 13 - Jul 18
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For Your Every Summer RSVP, with Code: SUMMER15
Description
HKS Super Fire Racing Spark Plug 50003-M40ILM Series Super Fire Spark Plugs HKS M Series spark plugs are high performance Iridium plugs designed to provide improved ignition performance, durability and anti carbon build up. 0. 6mm Iridium Alloy Center Electrode Outer Electrode with Platinum Chip Short Type Outer Electrode (Anti Vibration) Thermal Edge Spark Support Gap M Series is recommended for reliable ignition, durability and anti carbon buildup under high load. The Iridium alloy is used
M-Series Super Fire Spark Plugs
HKS M-Series spark plugs are high performance Iridium plugs designed to provide improved ignition performance, durability and anti-carbon build-up.
- 0.6mm Iridium Alloy Center Electrode
- Outer Electrode with Platinum Chip
- Short Type Outer Electrode (Anti-Vibration)
- Thermal Edge
- Spark Support Gap
M Series is recommended for reliable ignition, durability and anti-carbon buildup under high load.
The Iridium alloy is used because of its durability and reliability. On an average plug, a narrow core typically shortens life span of plug but with the intense durability of iridium there is no sacrifice in any longevity. With a high melting point of 2454 degrees C, opposed to the 1769 degrees C of white gold, the electrode can tolerate the high levels of compression and minor knocking without any deterioration. A nickel coating on the housing also prevents the spark plug from premature deterioration. The Iridium plugs are available for multiple applications and offered in "colder" heat ranges of 7 and up and specifically for rotary, heat ranges of 9 and up are offered.
Heat Range: NGK # 8
Thread Size: 14mm × 26.5mm
Wrench Size: 16mm
Fits:
| 2005 - 2005 | BMW | 325I | ALL | 2.5 | ALL | ALL | From 10/2005 Production Date | ABA-VS25 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2005 - 2005 | BMW | 325I | ALL | 2.5 | ALL | ALL | From 4/2005 Production Date | ABA-VB25 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2006 - 2006 | BMW | 330I | ALL | 3.0 | ALL | ALL | From 4/2005 Production Date | ABA-VB30 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2006 - 2006 | BMW | 330XI | ALL | 3.0 | ALL | ALL | From 10/2005 Production Date | ABA-VD30 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2010 - 2010 | BMW | 528I | ALL | 3.0 | ALL | ALL | From 3/2010 Production Date | DBA-FR30 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2006 - 2007 | BMW | 530I | ALL | 3.0 | ALL | ALL | From 6/2005 Thru 6/2007 Production Date | ABA-NE30 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2006 - 2007 | BMW | 530I | ALL | 3.0 | ALL | ALL | From 6/2005 Thru 6/2007 Production Date | ABA-NL30 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2007 - 2007 | BMW | 530XI | ALL | 3.0 | ALL | ALL | From 6/2007 Thru 3/2010 Production Date | ABA-PV30 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2006 - 2008 | BMW | Z4 | ALL | 3.0 | ALL | ALL | From 4/2006 Thru 5/2009 Production Date | ABA-BU30 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2006 - 2008 | BMW | Z4 | ALL | 3.0 | ALL | ALL | From 4/2006 Thru 5/2009 Production Date | ABA-DU30 Chassis | Coupe | Stock Plug/Heat Range: LONGLEACH:6 |
| 2005 - 2010 | HONDA | CIVIC | L4 | 1.3 | ELECTRIC/GAS | LDA1 | From 11/2005 Thru 12/2010 Production Date | FD3 Chassis | HYBRID | Stock Plug/Heat Range: LONGREACH:5 |
| 2009 - 2014 | HONDA | INSIGHT | L4 | 1.3 | ELECTRIC/GAS | LDA3 | From 2/2009 Thru 3/2014 Production Date | ZE2 Chassis | HYBRID | Stock Plug/Heat Range: LONGREACH:5 |
| 2003 - 2007 | INFINITI | G35 | ALL | 3.5 | ALL | VQ35DE | From 1/2002 Thru 10/2006 Production Date | PV35 Chassis | Stock Plug/Heat Range: LONGREACH:5 | |
| 2003 - 2007 | INFINITI | G35 | ALL | 3.5 | ALL | VQ35DE | From 1/2003 Thru 10/2006 Production Date | CPV35 Chassis | Coupe | Stock Plug/Heat Range: LONGREACH:5 |
| 2015 - 2016 | LEXUS | NX200T | L4 | 2.0 | ALL | 8AR-FTS | From 7/2014 Production Date | AGZ10.15 Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
| 2007 - 2008 | LEXUS | RX350 | ALL | 3.5 | ALL | 2GRFE | From 3/2005 Thru 11/2008 Production Date | GSU31W/GSU35W Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
| 2009 - 2015 | LEXUS | RX350 | ALL | 3.5 | ALL | 2GRFE | From 1/2009 Production Date | GGL10W Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
| 2003 - 2005 | MERCEDES-BENZ | C230 | ALL | 1.8 | ALL | ALL | From 6/2004 Thru 8/2005 Production Date | GH/DBA-203040 Chassis | Stock Plug/Heat Range: LONGLEACH:6 | |
| 2003 - 2005 | MERCEDES-BENZ | C230 | ALL | 1.8 | ALL | ALL | From 6/2004 Thru 8/2005 Production Date | GH/DBA-203040 Chassis | Wagon | Stock Plug/Heat Range: LONGLEACH:6 |
| 2006 - 2006 | MITSUBISHI | LANCER | ALL | 2.0 | ALL | 4G63 | From 8/2006 Thru 9/2007 Production Date | CT9A Chassis | DOHC MIVEC | Stock Plug/Heat Range: LONGREACH:7 |
| 2006 - 2006 | MITSUBISHI | LANCER | ALL | 2.0 | ALL | 4G63 | From 3/2005 Thru 7/2006 Production Date | CT9A Chassis | DOHC MIVEC | Stock Plug/Heat Range: LONGREACH:7 |
| 2003 - 2006 | NISSAN | 350Z | ALL | 3.5 | ALL | VQ35DE | From 1/2002 Thru 12/2006 Production Date | Z33 Chassis | Stock Plug/Heat Range: LONGREACH:5 | |
| 2003 - 2006 | NISSAN | 350Z | ALL | 3.5 | ALL | VQ35DE | From 10/2003 Thru 12/2006 Production Date | HZ33 Chassis | Roadster | Stock Plug/Heat Range: LONGREACH:5 |
| 2003 - 2007 | NISSAN | MURANO | ALL | 3.5 | ALL | VQ35DE | From 9/2004 Thru 8/2008 Production Date | PZ50/PNZ50 Chassis | Stock Plug/Heat Range: LONGREACH:5 | |
| 2009 - 2014 | SUBARU | IMPREZA | ALL | 2.5 | ALL | EJ257 | From 2/2009 Thru 7/2014 Production Date | GRF Chassis | Wagon | Stock Plug/Heat Range: LONGREACH:6 |
| 2010 - 2014 | SUBARU | IMPREZA | H4 | 2.5 | ALL | EJ257 | From 7/2010 Thru 7/2014 Production Date | GVF Chassis | Sedan | Stock Plug/Heat Range: LONGREACH:6 |
| 2003 - 2009 | SUBARU | LEGACY | H6 | 3.0 | ALL | EZ30D | From 9/2003 Thru 5/2009 Production Date | BLE Chassis | AVCS DOHC | Stock Plug/Heat Range: LONGREACH:6 |
| 2009 - 2014 | SUBARU | LEGACY | H4 | 2.5 | ALL | EJ255 | From 5/2009 Thru 6/2014 Production Date | BM9 Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
| 2003 - 2009 | SUBARU | OUTBACK | H6 | 3.0 | ALL | EZ30D | From 10/2003 Thru 5/2009 Production Date | BPE Chassis | AVCS DOHC | Stock Plug/Heat Range: LONGREACH:6 |
| 2008 - 2009 | SUBARU | OUTBACK | H4 | 2.5 | ALL | EJ255 | From 5/2008 Thru 4/2009 Production Date | BPH Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
| 2009 - 2014 | SUBARU | OUTBACK | H6 | 3.6 | ALL | EZ36D | From 5/2009 Thru 9/2014 Production Date | BRF Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
| 2005 - 2009 | TOYOTA | 4RUNNER | ALL | 4.0 | ALL | 1GRFE | From 8/2005 Thru 7/2009 Production Date | GRN215W Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
| 2006 - 2012 | TOYOTA | RAV4 | ALL | 3.5 | ALL | 2GRFE | From 8/2007 Production Date | GSA33W Chassis | Stock Plug/Heat Range: LONGREACH:6 | |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.3 ★★★★★
Based on 2390 reviews
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Product Reviews
★★★★★ 5
Comfy, thick, bottoms slick enough to wipe clean easily
Color: Long Black, Size: 10-13
Comfy, thick, bottoms easy to wipe clean . Would buy again. A little hot if anything.
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Reviewed in the United States on July 17, 2025
★★★★★ 5
Perfect to where around the house
Color: Long Navy, Size: 7-9.5
They worked perfectly. They fit very well.
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Reviewed in the United States on October 26, 2025
★★★★★ 5
Absolute game changer for chronically dry feet/cracked heels
Size: S (up to size 7)-Beige
I had recently bought a pair of silicone heel/ankle wraps to fill out my boot a little since I noticed my heels were lifting when I was skating. I tested them out around the house and noticed they left my heels softer while the rest of my sockless feet got quite dry. So I got these full foot silicone socks to see the effect of having my whole foot covered. I slather the entirety of my feet with Dr. Scholl's Severe Cracked Heel Restoring Balm (love how convenient it is to apply it to my feet with the solid stick form) and then slip them into these silicone socks. After just a couple hours, when I pull out my feet they're (a teeny bit sweaty at first), but then overall soft and smooth and have absorbed the balm fully leaving barely any residue in the silicone sock. I find these silicone socks generally comfortable; I wear them in the evenings while relaxing on the couch, take them off after a couple hours and let my feet breathe a bit, and then reapply my balm and socks and wear them to bed. If I wake up in the middle of the night, which I almost always do (not because of the socks), I'll take the socks off and allow my feet to breathe again. I wear a woman's size 6 shoe and the small size is pretty comfortable. However, I made the mistake of wearing them while being on my feet for a couple hours straight during household chores -- they must've somehow cut off my circulation a bit with the standing, so I wouldn't recommend wearing these silicone socks while being active. And since they're not exactly my foot size, they slide around sometimes and will start to feel tight at my big toe. But if that happens, I just tug on the toe area of the sock to give my big toe more wiggle room and problem solved. Prior to wearing these socks, I was soaking and doing heavy duty exfoliation of my feet every week. These socks seem like they'll work to help me extend the time between soakings and exfoliations. The 5 pack is a great value. So far none have torn, so they seem rather durable. Not sure what I could even do to tear a hole in these.
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Reviewed in the United States on January 16, 2026
★★★★★ 5
Works wonders
Size: M (up to size 9)-Beige
Works wonders for dry feet, like really dry, hard feet.
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Reviewed in the United States on February 23, 2026
★★★★★ 4
EXCELLENT FEET MOISTURE PROTECTION
Size: S (up to size 7)-Beige, Size: S (up to size 7)-Beige
Why did you pick this product vs others?:
I have burns on my feet and needed something that I could put burn creme on and still walk around in with. I tried other silicone footsie but they would teae really easily. So far these are doing really well for this purpose. They are holding their shape too. The only caution I have is the same with all silicone footsies: They can be slippery on wet floors, so also wear with socks over them.
The biggest issues is when they say a size they mean it. The silicone used in these have little give in them, so they won't stretch out and loose their shape. That can be a good thing, or not so good, depending on how well they fit your feet and what your intent is with wearing these. The other issue is if they fit snug around those toes, that tends to be where the first tear in the material will happen. Because of how these are made, the tear is actually more like cracking in the material and once it occurs you won't be able to get much use out of the sock after that. If you are planning to wear them around the house or for long term use, I suggest going up a size or look for the toeless options.
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Reviewed in the United States on July 5, 2025