4 KudoZ points awarded for this answer. Comment: "Well what can I say? Thanks to you all of course. For Golub, you deserved the points for your pun, but I'm distrustful of Briotti's translator (could'a been me!). For Paola: your interesting site suggests an alternative line of work that will surely pay much better than our current occupation. ;-) For Kara, with the hands-on approach and helpful engineers; although I might not use "directional converter", it's certainly worth a thought. Trouble seems to be that this type of locking system is not much used in English-speaking countries. I will let you know if the manufacturer happens to know the "correct" term. Cheers Derek"