Signal Dynamics Headlight Strobe Module Adapter Harness Features This is the harness you need if your bike has an H4 connector on the headlight when installing the Signal Dynamics Corporation Plug and Play Headlight Modulator Will work with both single and dual headlight motorcycles This module works with most Harley Davidson Motorcycles or motorcycles that use a Dual Filament Bulb Note: Requires the Signal Dynamics Corporation Plug and Play Headlight Modulator 445-956