Polaris 440 Pro X Brake Bulb Size

The Polaris 440 Pro X brake light utilizes 1157 and 921 bulb sizes depending on the specific version of the machine. Data for the bulb sizes covers the range from 2001 to 2003.

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
2003	1157	P21/5W	Check Price
2001-2002	921	W16W	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
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921	Check Price

Other Locations

Additional Notes

The 921 bulb is a T15 wedge type operating at 12V and 16W. Its wedge base design requires no separate socket locking mechanism, as the bulb is held in place by tension from the housing itself.
The 1157 bulb uses a BAY15d bayonet base and carries a dual-filament configuration rated at 12V with separate 21W and 5W filaments. The higher-wattage filament serves the brake function, while the lower-wattage filament handles a secondary role such as running light duty.
Both bulb types conform to ANSI standards applicable in the United States and Canada, meaning their physical and electrical specifications follow a defined industry classification rather than a proprietary format.
The Polaris 440 Pro X uses the 921 bulb for the 2001-2002 model years and transitions to the 1157 for the 2003 model year. These two bulbs are not interchangeable, as they differ in base type, filament count, and wattage.
The shift from a single-filament wedge bulb to a dual-filament bayonet bulb between model years indicates a change in the brake light circuit design, which affects socket compatibility at the housing level.