Ski-Doo MX Z 440 X Brake Bulb Size

The Ski-Doo MX Z 440 X brake components utilize 921 and 1157 bulb sizes for the lighting systems. Available information covers the production span from 2001 through 2007.

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	Bulb Size
2004-2007	921
2001-2003	1157

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157

Other Locations

Additional Notes

The Ski-Doo MX Z 440 X uses two distinct brake bulb types across its 2001-2007 model years: the 921 and the 1157, both conforming to ANSI standards recognized in the US and Canada.
The 921 is a T15 wedge-base bulb rated at 12V and 16W, fitted to the 2004-2007 model years.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W/5W output, fitted to the 2001-2003 model years.
The dual-filament design of the 1157 means it carries two separate filaments within a single envelope, one for braking intensity and one for a lower-draw running light function, which the single-filament 921 does not replicate.
The 921 wedge base and the 1157 BAY15d bayonet base are physically incompatible mounting types, making the two bulbs non-interchangeable despite both operating on a 12V system.
The wattage difference between the 921 at 16W and the 1157 brake filament at 21W reflects a difference in light output and circuit load, which is relevant to socket and wiring compatibility.