This ceiling panel is unpainted with fully perforated square holes in a regular pattern and is backed with a special non-woven lining. It has excellent sound absorpation properties when backed with glass wool insulation matt. Pro square is a sound absorptive perforated plasterboard with recessed edges available in either square, round or slotted design perforations. Pros square is recommended for use as wall or ceiling lining where sound absorption is required. It is also ideal for decorative applications. Physical Properties