The Durabase 30 in. x 60 in. Single Threshold Shower Floor in White features a right-hand drain opening that is offset 15 in. x 8-1/2 in., the same as a bathtub, to help make replacing a bathtub easy. This barrier-free shower floor meets ADA specifications 07/01/1997 and can be used with entry ramp model # 360.100 (sold separately).