Kubota RTV500 4x4 Turn Signal Bulb Size

The Kubota RTV500 4x4 turn signal utilizes a P21/5W bulb size for the lighting components. Data for the specified equipment covers the period from 2015 through 2018.

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
2015-2018	P21/5W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W

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Additional Notes

The Kubota RTV500 4x4 uses the P21/5W bulb for its turn signal function across the 2015-2018 model years.
The P21/5W is an ECE-standard bulb, meaning it conforms to European and internationally recognized automotive lighting regulations rather than SAE standards used in North American markets.
This bulb type is dual-filament, with one filament rated at 21 watts and a second rated at 5 watts, allowing a single bulb to serve two distinct lighting functions within the same housing.
The P21/5W uses a BAY15d bayonet base, which is an offset twin-pin base. The two pins are positioned at different heights, which prevents incorrect insertion and ensures the filaments align properly within the fixture.
The bulb operates on a 12-volt electrical system, consistent with the standard low-voltage DC architecture found in most utility vehicles of this class.
Because the BAY15d base has an asymmetric pin layout, it is not interchangeable with the single-filament BA15s base or the symmetric twin-pin BAY15s base, even though those bases share a similar physical form factor.