There are several companies doing them, most customised to suit particular controllers. Can't remember who made the ones I bought, don't quite look the same as yours, but have found them useful. Alternatively DCC Concepts sell a plastic version or for NCE users a more Roll Royce version Complete with lanyard Paul
I made flat aluminium 'hooks' for the backs of my Lenz LH100 controllers with matching plates to hang on the front edge of my 00 layout. Keith.
