Yes, that's the one .If there aren't any available would someone be able to 3d print some for me? I posted this in the 3d print group on Facebook on Facebook but I haven't gotten a response yet. I've sent out numerous requests to a number of different sources but I have yet to get a reply except to say that they would probably have to be 3d printed.I did find one person who said they had some but he didn't have the 18mm size.