Metal housing with nylon concave wheel. No measurement taken. Hopefully you can identify the exact size by the marking.
60-03 sometimes with a small 5 after the 3, i.e 60-03 5, with the 5 being smaller than the other digits.
Dave Sr. from SWISCO responded:
March 31, 2017
I believe you have our older corner key which is unfortunately not available anymore. That said, the manufacturer suggests using the 84-026 as a substitute. See if that matches up to yours.