Coupling damper /shock absorber /  for AL-KO coupling model 150V.
 
MPN 690389
530mm long to the end of the thread.
Thread length 40mm 
 
Fits couplings with ETI Number -
811245
811273
811289
811298
811610
811831
811824
 
The ETI number is made up of 6 digits beginning 811, this can be found on the details stamped on the green oval ID plate fitted on top of the coupling body (On a caravan this may be under the cowling).