Oversized stack chairs are weight-tested to hold 500 lb. to accommodate all visitors or participants. 3-1/2" thick seat & back are upholstered in antimicrobial vinyl to protect the product from germ & prolong its life. Seat measures 21" wide x 15" deep. Back size is 20-1/2" wide x 19-1/2" high. Durable, 18-gauge steel frame with four-leg base is powder-coated in black for durability. Armless chairs stack five high.