Collection: Bulbs W21W

W21W automotive bulbs – how to select the correct type

The W21W is a capless 21 W glass bulb used in certain indicators, reversing and brake lights. The designation identifies a light-source type, but fitment depends on the vehicle and lamp manufacturer's requirements.

What to check before buying

Check the marking on the old bulb or in the vehicle manual. Verify the base or socket, dimensions, contact arrangement, voltage, rated power and intended function where relevant. Do not assume that similar-looking bulbs are interchangeable, and check the contents of multipacks.

Replacement and safety

Switch off the lighting and allow the bulb to cool before replacement. Install the correct approved light source securely in its fitting. Avoid touching the glass with bare fingers where the manufacturer advises against it. Check that the lights operate correctly and that their alignment is appropriate.

Explore automotive bulbs and compare product specifications with your vehicle's documentation.