Architectural Frames in Molded Plastic is a round and square corner system designed for quality interior signage. Nine different sizes can be interchanged to enhance any interior. All frames have a 1/2" outside depth, 1/8" thick walls and mounting holes for attaching to walls. The size of each frame is listed as an inside dimension and the inside radius on the round corner frames is 5/16". Each frame is designed to accommodate all sign material from 1/16" to 1/8" thick.