Freeman Gasket Material, neoprene, .56 x .55 x .44?. Standard Freeman hatch gasket material. It measures a top width of .56?, bottom width of .44? and a height of .55?. It is made of neoprene and has a durometer rating of 25. This gasket provides a secure seal, protecting closures from the onslaught of elements in the demanding marine environment. Sold by the foot.