Seats are rotationally molded and made from SURPASS® materials. Molded in 1/4"-20 T-nuts accepts most pedestals.Tufted removable cushions of the highest quality in it's class accent this seat. The back is made from starboard, supported by heavy anodized aluminum brackets. 20 3/4"D x 24 1/8"W x 21 3/4"H.