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Ships within 48 hours · Estimated delivery Jul 29 - Aug 3
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For Your Every Summer RSVP, with Code: SUMMER15
Description
HKS Super Fire Racing Spark Plug 50003-M40M 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 × 19mm
Wrench Size: 16mm
Fits:
| ACURA | INTEGRA | ALL | 1.8 | B18A1 | 1991 - 1993 | DB1 Chassis | DOHC | Stock Plug/Heat Range: JIS:6 | From 10/1991 Thru 4/1993 Production Date |
| ACURA | LEGEND | V6 | 2.5 | C25A1 | 1985 - 1987 | KA2 Chassis | Stock Plug/Heat Range: JIS:6 | From 10/1985 Thru 2/1987 Production Date | |
| ACURA | LEGEND | V6 | 2.7 | C27A1 | 1987 - 1990 | KA3/KA6 Chassis | Stock Plug/Heat Range: JIS:6 | From 2/1987 Thru 9/1990 Production Date | |
| HONDA | CIVIC | L4 | 1.5 | D15B2 | 1987 - 1989 | EF2/EF4 Chassis | Stock Plug/Heat Range: JIS:6 | From 9/1987 Thru 9/1989 Production Date | |
| HONDA | CIVIC | L4 | 1.5 | D15B2 | 1989 - 1991 | EF2/EF4 Chassis | Stock Plug/Heat Range: JIS:6 | From 10/1989 Thru 8/1991 Production Date | |
| HONDA | CIVIC | L4 | 1.5 | D15B7 | 1992 - 1996 | EY4 Chassis | Stock Plug/Heat Range: JIS:6 | From 10/1992 Thru 2/1996 Production Date | |
| HONDA | CRX | L4 | 1.5 | D15B2 | 1987 - 1989 | EF6 Chassis | Stock Plug/Heat Range: JIS:6 | From 9/1987 Thru 9/1989 Production Date | |
| HONDA | CRX | L4 | 1.5 | D15B2 | 1989 - 1991 | EF6 Chassis | Stock Plug/Heat Range: JIS:6 | From 9/1989 Thru 2/1992 Production Date | |
| HONDA | PRELUDE | L4 | 2.0 | B20A5 | 1985 - 1991 | BA1/BA4/BA5 Chassis | DOHC | Stock Plug/Heat Range: JIS:6 | From 10/1985 Thru 9/1991 Production Date |
| HONDA | PRELUDE | L4 | 2.0 | B20A5 | 1987 - 1991 | BA4/BA5 Chassis | Stock Plug/Heat Range: JIS:5 | From 4/1987 Thru 9/1991 Production Date | |
| HONDA | PRELUDE | L4 | 2.0 | B20A5 | 1989 - 1991 | BA5 Chassis | DOHC TCS | Stock Plug/Heat Range: JIS:6 | From 11/1989 Thru 9/1991 Production Date |
| LEXUS | ES300 | ALL | 3.0 | 3VZFE | 1992 - 1996 | VCV10 Chassis | Stock Plug/Heat Range: JIS:6 | From 10/1991 Thru 8/1996 Production Date | |
| MAZDA | 626 | L4 | 2.0 | ALL | 1987 - 1989 | GDER/GDEA/GDEP/GDEB/GDES Chassis | DOHC | Stock Plug/Heat Range: JIS:6 | From 5/1987 Thru 5/1989 Production Date |
| NISSAN | 180SX | ALL | 1.8 | CA18DET | 1989 - 1991 | RS13/KRS13 Chassis | Stock Plug/Heat Range: JIS:6 | From 4/1989 Thru 1/1991 Production Date | |
| NISSAN | 300ZX | V6 | 3.0 | VG30T | 1984 - 1989 | HZ31/HGZ31 Chassis | Stock Plug/Heat Range: JIS:6 | From 9/1983 Thru 6/1989 Production Date | |
| NISSAN | PULSAR NX | ALL | 1.6 | CA16DE | 1987 - 1987 | EB12 Chassis | Stock Plug/Heat Range: JIS:6 | From 8/1986 Thru 1/1990 Production Date | |
| NISSAN | SKYLINE | ALL | 2.0 | RB20DE | 1989 - 1991 | HR32/HCR32/HNR32 Chassis | Stock Plug/Heat Range: JIS:5 | From 5/1989 Thru 8/1991 Production Date | |
| NISSAN | SKYLINE | ALL | 2.0 | RB20DET | 1989 - 1991 | HCR32/HNR32 Chassis | Stock Plug/Heat Range: JIS:5 | From 5/1989 Thru 8/1991 Production Date | |
| NISSAN | SKYLINE | ALL | 2.5 | RB25DE | 1991 - 1993 | ECR32/ER32 Chassis | Stock Plug/Heat Range: JIS:5 | From 8/1991 Thru 8/1993 Production Date | |
| NISSAN | SKYLINE | ALL | 2.6 | RB26DETT | 1989 - 1994 | BNR32 Chassis | Stock Plug/Heat Range: JIS:6 | From 8/1989 Thru 1/1995 Production Date | |
| NISSAN | SKYLINE | ALL | 2.6 | RB26DETT | 1995 - 1998 | BCNR33 Chassis | Stock Plug/Heat Range: JIS:6 | From 1/1995 Thru 1/1999 Production Date | |
| NISSAN | SKYLINE | ALL | 2.6 | RB26DETT | 1999 - 2002 | BNR34 Chassis | Stock Plug/Heat Range: JIS:6 | From 1/1999 Thru 8/2002 Production Date | |
| TOYOTA | CELICA | ALL | 2.0 | 3SFE | 1987 - 1989 | ST162 Chassis | Stock Plug/Heat Range: JIS:5 | From 8/1987 Thru 8/1989 Production Date | |
| TOYOTA | CELICA | ALL | 2.0 | 3SGELC | 1987 - 1989 | ST162 Chassis | Stock Plug/Heat Range: JIS:5 | From 8/1985 Thru 8/1989 Production Date | |
| TOYOTA | CELICA | ALL | 2.0 | 3SGTE | 1988 - 1989 | ST165 Chassis | Stock Plug/Heat Range: JIS:5 | From 10/1986 Thru 8/1989 Production Date | |
| TOYOTA | COROLLA | ALL | 1.6 | 4AFE | 1988 - 1992 | AE95 Chassis | Stock Plug/Heat Range: JIS:5 | From 5/1988 Thru 5/1992 Production Date | |
| TOYOTA | COROLLA | ALL | 1.6 | ALL | 1985 - 1987 | AE86 Chassis | Stock Plug/Heat Range: JIS:5 | From 6/1983 Thru 5/1987 Production Date | |
| TOYOTA |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
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Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
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4.0 ★★★★★
Based on 24 reviews
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Product Reviews
★★★★★ 3
Comfy but smelly
Size: King (2 Pack)
These expand quickly and are comfortable, but they smell like chemicals faintly.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 1, 2026
★★★★★ 5
Love these pillows!
Size: Queen (2 pack)
I’m a side and stomach sleeper. I’ve bought so many pillows recently trying to find one that doesn’t kill my neck or shoulder. I felt like I was looking for a unicorn. For some reason this pillow just works. It has a higher loft, which I prefer, but it’s also super squishy, which I also prefer. It somehow has the best of both worlds. They feel high quality, are adjustable in terms of density since you can remove as much filling as you want, they actually fill my pillowcases so they’re not flopping around the pillow, and they maintain their shape after a full night of sleeping on them, the price point for two pillows is just right, and best of all, they actually stay cool. I am a hot sleeper so that last point is worth the cost of entry all by itself. I have no neck or shoulder pain after getting a full night’s sleep on these pillows. The only negative is the initial smell of the pillows. It’s pretty strong, but I’m sure this will lessen over time.
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Reviewed in the United States on April 3, 2026
★★★★★ 5
Soft and cool.
Color: Cooling Blue Cover, Size: Queen (Pack of 2)
Love this pillow set. Comfortable addition and nice and cool at all times. Going to be great for when the hot weather hits
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Reviewed in the United States on June 8, 2026
★★★★★ 5
As advertised for once! Lol
Color: Cooling Blue Cover, Size: Queen (Pack of 2), Color: Cooling Blue Cover, Size: Queen (Pack of 2)
Queen size set of 2 pillows, I'm giving it 5stars first bc it has a good length and width!! If you've ever bought memory foam pillows before you know some are small!! Anyways after having it for 5nights, we loved that me and my huddy could adjust the Thickness amount we had in it to our needs, me needing a thick pillow and my husband needing a flatter one. So this was perfect for that. So far its nice to sleep on, stays cool, doesnt get hot. I would say its on the frimer side but softer the more foam you take out! Really its just good for the amount you spend!! Will it last 10years probably not but what does now a days. This is the only time my huddy n I bought the same pillow and both love it so I'm just still in shock it worked out so well!!
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Reviewed in the United States on April 28, 2026
★★★★★ 5
Adjustable pillows
Color: Cooling Blue Cover, Size: Queen (Pack of 2)
I love these because they don't go flat. You can pull out whatever you need to make them comfy for you. They come in two different layers. So you have that protective cover over the main case that holds the memory foam. They're amazing to sleep on. I have had these last for years without going flat. If you hate flat pillows this is the way to go. They are very easy to wash. You just have to separate layers. They are very thick, you can adjust the thickness. Everyone in my house has at least one. They are worth the money. I have never had to replace them, because they went flat.
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Reviewed in the United States on May 6, 2026
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