Indexed Spark Plugs align the open end of the electrode towards the intake port.

The hottest flame meets the new fuel charge for a performance gain, increases h.p, fuel mileage, & plug life.

This is a speed secret car racers have used for years. You simply mark the electrode side of the plug with a magic marker on the porcelain. You then shim the plug with washers to align the electrode towards the intake port. Fits 14mm plugs.

4 washers in each kit.

red= 1.68mm  Blue= 1.23mm  Silver 1.04mm  Gold= .91mm

Major two stroke tuning secret!