Works on Flat and Angled Curbs Assists Water Back Into Shower Rounded for Protection Clear Acrylic Frameless Shower Door Thresholds prevent water leakage and assists water back in towards shower. The Threshold can be applied with a Mildew Resistant Silicone Sealant. The rounded design protects feet from harm. The Acrylic Threshold can be used in conjunction with bottom door sweeps. Material: Clear Acrylic Length: 72" Height: 1/2" Width: 1"