Hornby Pack of 10 NEM Couplings R8220NEM Couplings
This is a pack of ten replacement NEM plug-in couplings of a new design. The tension-lock principle has been abandoned and a slim 'clasp' design used instead. As the vehicles are pushed together the toothed couplings slide past each other but when the tension is taken up the 'barbs' engage and grip. One disadvantage could be unintentional disengaging if there is too much vertical play due to poorly laid track. Hornby say that they work particularly well when close-coupling their new Gresley and Stanier coaches.
[Source: Model Railway Express MAG]
Hornby have two products:
NEM close couplings (R8219)
NEM pocket coupling (R8220)
These couplers are now available at £3.50 for 10. They seem to be exactly like Roco coupler, if not the Roco coupler.
I'm not sure if these are the Roco items, I have asked Hornby and await a reply. Here are the Roco items:
Hornby NEM Close coupling - R8219 Look at the item at Hattons here.
Roco Close coupling
Roco Pocket coupling
Hornby NEM coupling - R8220 Look at the item at Hattons here.