WIDE APPLICATION: This shower head bracket fits round shower riser rail of 19-22 mm O.D. You can adjust the size of the clamp holder to clamp the shower head bracket to the rail flexibly through the knob at the end position. For the size of the slot for the showerhead, the top of the opening is 0.85" (22mm) in diameter. The bottom of the opening is 0.75" (19mm) in diameter. Note: Do not tighten the knob too tight, and do not tighten it with a spanner. 360 DEGREE ROTATION: The shower head holders can rotate 360 degrees freely. To make it easier to adjust the spray angle, you can tighten or loosen the bracket screw according to the weight of your shower. EASY INSTALLATION: No tools are needed, no need to disassemble the shower slide bar, just loosen the knob at the end of the shower holder bracket, then it can be installed on the shower slide bar. PROTECTIVE AND ANTI-SLIPPING DESIGN: Built-in silicone pad, to keep the shower holder in place and protect the shower slider rail from daily scratches. DURABLE CONSTRUCTION: The shower head holder is made of engineering-grade ABS material. Coated with industry-leading chrome finish, build to resist daily scratches and corrosions. Colour:Polished Chrome Material:Acrylonitrile Butadiene Styrene Finish type:Polished Shape Round Item dimensions L x W x H:12.5 x 3.7 x 3.7 centimetres Package include:1*shower head bracket