These timing retard controls from Fast are an ideal way to add zero to 20 degrees of timing retard in three modes--continuous, demand, and boost proportional--to HI-6, HI-6R, and HI-6DSR ignition systems. The sealed units can be mounted under the dash, and an LED light comes on when retard is commanded. Use them with the optional boost (MAP) sensor for boost proportional retard. They're compatible with nitrous, turbo, and supercharged on-demand retard hookup, and are not intended for underhood mounting.