A quick learner from Hamburg, Germany says:
January 11, 2016
I need several replacement mirror wardrobe door roller very similar to your Product Code: 23-064. There are some differences (e.g. my wheel is 1.5 inches) but the key similarity is the the ledge that sticks out to hold the door. I have looked everywhere but have found nothing that is as similar as this. The only identifying info on the part is the patent number 4850145 and the letters THM underneath. Hope you can help.
Paul from SWISCO responded:
January 12, 2016
I don't think your roller is available anymore. See our 23-028 instead. Could you possibly use this as a match? If not, take a few pictures of your roller just so that we can make sure we're thinking of the same part.