Somewhere on the body of the coupling (not the coupling head), there should be an ID plate. This plate should contain the manufacturers name, a type number and weight of the coupling. This is often most of the information that is needed to figure out what parts is fitted. If you can’t find what you’re looking for, use the below form.
Common manufacturers:
Al-ko. Type number 6 digits beginning 811 (ID plate is a green oval)
Avonride. Might have Maesteg – CF34 0AQ. Type number AC or AV followed by weight
Knott. Type numbers KFG, KRV, KF followed by weight
Bradley. Type numbers begin with HU or EH
BPW. Coupling numbers begin 48.27.58
Indespension. Type numbers start V67 or CP
These are just guidelines; over the years different numbers have used.

If you still need help, please don’t hesitate to email us with as much of the following information you can:
Coupling make, coupling model, coupling weight and parts needed

Photos of the coupling can be every useful.