The H21W bulb is an automotive bulb commonly used as a brake light, tail light, or indicator light. It has a single filament and operates at a nominal power of 21 watts with a voltage of either 12 or 24 volts. The bulb is designed with a BAY9s base, which is a type of bayonet base that allows for easy installation and removal.
H21W Light Bulb
BULB CROSS REFERENCE
The H21W light bulb family is interchangeable with the following bulbs
H21W bulb is not suitable for use as a headlight bulb. Additionally, it is important to note that the H21W bulb is not interchangeable with other bulb types, as it has a unique base and power specifications.
Overall, the H21W bulb is a reliable and long-lasting option for automotive lighting needs. Its single filament design and bayonet base make it easy to install and replace, while its 21 watt power output provides ample brightness for its intended applications. If you need a replacement bulb for your brake light, tail light, or indicator light, the H21W bulb is a great choice.