MSD Ignition RPM Activated Switches Features: Activate/Deactivate A Circuit/Different RPM Points Use With Stock Or MSD Ignitions Use RPM Modules To Set RPM Point Activate A Circuit And One RPM Point Turn Off The Same Circuit At A Different RPM Great to Control A Nitrous System Circuits That Require Over 1.5 Amps See MSD Relays Height: 5.00 Width: 1.50 Length: 3.50 Weight: 0.50 lbs