This plastic bathtub grab rail supports the user during entry and exit of the bathtub to ensure safety in the bathroom. The ergonomic grab handle design provides a secure and comfortable hand position. To fit the bathtub grab rail onto a bathtub, simply turn the side knob and the clamp width adjusts to fit your bathtub wall. No tools are required for installation. Fits bathtub walls 3" to 6.5" wide. Not for use with fiberglass bathtubs.