Dedenbear RPM Activated Switch (DE-RPM2)DEDENBEAR RPM SWITCH Part Number: DE RPM2 RPM activated switches are nothing new, but for the price, you wouldn't expect this kind of accuracy! This box has been refined to an exact science. Change your shift point in 100 rpm increments by simply pressing the thumb wheels No more fumbling around looking for "chips". Repeatability of + 1 rpm, means each shift, each pass will be virtually identical. Works with any MSD Electronics ignition system.