B22 Base
A bayonet cap base with a 22mm diameter, standard in the UK, Australia, and parts of Asia. Push-and-twist to lock into the socket.
B22 is the bayonet cap fitting that dominates in the UK, Australia, India, and several other countries. Instead of screwing in like an Edison base, you push the bulb in and twist clockwise — two pins on the side of the base slot into grooves in the socket and lock with a spring.
The bayonet mechanism has a practical advantage: it's faster and more secure than a screw fitting. You can't accidentally over-tighten or strip the socket. This made it popular in markets where bulb changes needed to be quick and reliable — including industrial and public lighting.
LED B22 bulbs are widely available in the same shapes and specifications as E26/E27 versions. If you're reading a guide written for the US market and it mentions E26, the B22 equivalent will have the same specs — just a different base. The bulbs are otherwise identical in terms of wattage, lumens, color temperature, and CRI.
Specifications
| Diameter | 22mm |
| Type | Bayonet cap (push-twist) |
| Common in | UK, Australia, India |
Related Terms
- E26 / E27 Base
The standard Edison screw base used in most household lamps and fixtures. E26 (26mm) is the North American version, E27 (27mm) is the European equivalent.