If you make signs or anything else that is about 1/8" - 3/16" thick (3mm - 4mm) and are having problems with corner damage, here is a simple, inexpensive solution. These translucent slip-on corners have a small bump-out molded at the corner so even if you bang the edge of the sign accidentally it will not get damaged. They are about 1-3/4" (45mm) on each edge - visual size on board. The corners are 90% clear (our assessment - the point is they're not crystal clear) so you can see through them and they they blend in with whatever they're on. This is a great product! They usually ship same day from our Chicago warehouse. This box will do 250 signs. Need more? Also available in 2000 pc and7500 pc boxes. e-mail us for a specific quote.