XTREME RACING EHD 5 COLD TURBO GLOW PLUG THESE PLUGS ARE "EHD" (EXTRA HEAVY DUTY) TURBO PLUGS. THE PLUGS ARE DESIGNED FOR BIG BLOCK HIGH PERFORMANCE MOTORS RANGING FROM .21 TO .32 SIZE. THESE TURBO PLUGS ARE COLOR COATED FOR QUICK IDENTIFICATION. COLOR CODE RED = #5 COLD TURBO PLUG GREEN = #6 MEDIUM TURBO PLUG BLUE - #7 HOT TURBO PLUG *** INCLUDED WITH ITEM *** 1 - TURBO GLOW PLUG