9 gauge steel ZINC plated H frames. 10" x 30" with 7.5" prongs. Designed for 4 mil corrugated plastic. These frames are for 4mm corrugated plastic signs and are made to slip right up into the flutes, which make the sign and frame a very sturdy pair. One H frame is needed per sign except 2'x3' and 2'x4' we recommend two frames. Any sign above 2'x4' is too large for this frame.