The square is 1 in. and 1/4 inch thick. Image #9850 shows the broken piece - piece broke off into screen frame.
Dave Sr. from SWISCO responded:
May 24, 2023
Hello,
Unfortunately, we were not able to locate your exact corner key. With that being said, take a look at the 95-186 and 95-187. Review the specifications below to see if you could use either of these to repair your screen frame. Thank you.