Top is one piece 20-gauge stainless steel. Interior liner is 22-gauge stainless steel and is creased to 1.00" (2.54 cm) diameter drain. Unit has a sectional, removable perforated stainless steel false bottom and is provided with adapter bars to allow placement of 12" x 20" (30.5 cm x 50.8 cm) pans. Unit is supplied with 1" (2.54 cm) plastic drain to be installed by customer. Exterior housing is 22-gauge galvanized steel. Unit is insulated with high density closed cell polyurethane.