Should fit most vintage British machines with battery and 12V systems, see below:

Genuine Lucas 120W (max output 160W) single phase rectifier/regulator.
Supplied with superseal connectors and fly lead for connection to an existing loom.

Designed for use with Lucas single phase stator 47205, but not suitable for high output single phase stators
Can also be used to convert early 6V three lead stators to 12V.

Earth (Pos/Neg) : Both
Voltage : 12V
Single Phase : Yes

Supplied with everything shown, instructions.  We will answer questions promptly, thanks for looking.