Archboard features unique Lock-O-Matic dual arch rings and 1/8in brown hardboard. Locking feature on rings prevents the mechanism from being opened accidentally. Surface has a smooth finish on the front and back. Archboard holds letter-size and A4-size papers and offers a 2.5in capacity. Holds Paper Size: 8.5 x 11; Clipboard Actual Size: 9 x 15; Clipboard Material: Recycled Hardboard; Clip Capacity: 2.5in.