Ski-Doo Formula STX Tail Light Bulb Size

The Ski-Doo Formula STX tail light requires a 1157 bulb size for the rear lighting assembly. Data for the specified component covers the period from 1994 through 1996.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	US Type	EU Type	Shop
1994-1996	1157	P21/5W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157	Check Price
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W	Check Price

Other Locations

Additional Notes

The Ski-Doo Formula STX uses the 1157 bulb for its tail light across the 1994-1996 model years.
The 1157 is an ANSI-standardized bulb type recognized across the United States and Canada, meaning it conforms to a defined set of electrical and physical parameters shared by all compliant manufacturers.
This bulb operates on a dual-filament design, where one filament runs at 21W for braking or signaling functions and a second filament runs at 5W for a lower-intensity running light function.
The 1157 uses a BAY15d bayonet base, which features two offset locking pins at different heights on the base. This offset pin arrangement prevents accidental installation of single-filament bulbs that share the same general base style but carry a different pin configuration.
The bulb is rated at 12 volts, consistent with the standard electrical system voltage found in most powersports and automotive applications of this type.