SKU: 49925089645

HKS Super Fire Racing Spark Plug 50003-M50RE

Sale price$70.93 Regular price$78.81
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Description

HKS Super Fire Racing Spark Plug 50003-M50REM 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 # 10
Thread Size: 14mm × 12.7mm
Wrench Size: 20.8mm

Fits:

1983 - 1985 MAZDA RX-7 ALL ALL From 10/1983 Thru 9/1985 Production Date  SA22C Chassis  Stock Plug/Heat Range: ROTARY:9
1985 - 1988 MAZDA RX-7 R2 1.3 From 10/1985 Thru 8/1988 Production Date  FC3S/FC3C Chassis  Stock Plug/Heat Range: ROTARY:10,11
1988 - 1991 MAZDA RX-7 R2 1.3 From 9/1988 Thru 12/1991 Production Date  FC3S/FC3C Chassis  Stock Plug/Heat Range: ROTARY:7,9
1993 - 1995 MAZDA RX-7 R2 1.3 From 12/1991 Thru 8/2002 Production Date  FD3S Chassis  Stock Plug/Heat Range: ROTARY:7,9
Shipping Notes
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Exchange/Return Notes
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  • Final sale items are not eligible for returns or exchanges.
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SKU: 49925089645

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DL
Los Angeles, US
★★★★★ 4
High Quality
My husband is deficient in magnesium and these by far looked like they were of the highest quality . Not sure yet if they help him sleep better but will be purchasing them again.
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Reviewed in the United States on May 8, 2026
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David Hartnell
Houston, US
★★★★★ 5
Better sleep, better mood
This definitely helped my mood and sleeping. It literally changed my default. The only electrolyte that can pass the blood brain barrier. I recommend.
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Reviewed in the United States on May 9, 2026
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Jz
Whiting, US
★★★★★ 5
For better sleep and consultation and calming effect.
It seems to work for me, it makes me calm but energetic, plus I sleep for 8 hours since taking it.
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Reviewed in the United States on May 10, 2026
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Redirtgrl
Houston, US
★★★★★ 3
Not working for me 100%
Still not sure about how this magnesium affects me. I have only been taking one tablet an hour or two before bedtime. Seems like sometimes I can’t go to sleep after taking it, charges up my brain. Other times I sleep but have crazy dreams. Maybe it works for some, but not others. I’ll try to finish the bottle, but the lack of sleep after taking the Magnesium L-Threonate makes me hesitant to continue some nights. That’s mainly the reason I purchased this brand to include the reviews.
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Reviewed in the United States on February 12, 2026
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paul culling
Boise, US
★★★★★ 5
Helps Relax the muscles
I like to take a magnesium supplement daily, usually in the evening before going to be as it helps relax me for sleep
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Reviewed in the United States on May 3, 2026

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