Electronic Timer Assembly in polished billet finish for 1936-'69 HD® Big Twins. These polished billet electronic timers for generator style engines were developed to accommodate the S&S® Super Stock® Ignition system in complete S&S® generator style engines.It can also be used with other alternator style electronic ignitions (CCW rotation) as well. This timer comes with a reverse rotation circuit breaker gear installed for correct rotation direction for modern electronic ignitions. The S&S® billet timer must be used with reverse rotation circuit breaker drive gear in crankcase. Made of billet aluminum and polished to a show finish. Designed to be installed and removed without removing the cylinder head. Fits all S&S® stock, and other aftermarket generator crankcases for 1936-'69 engines.