There are two types of material offered for a bed cover:
Polycarbonate: This material will not crack under pressure like acrylic will. The drawback is under heavy pressures polycarbonate will become slightly spongy causing a pressure loss on the press. Due to this we do not recommend it for uses such as Aqua Tint, Mezzo Tint or Photo Gravure.
Acrylic: This material is less expensive but is not as durable as polycarbonate. Recommended for use with heavy pressure applications.