This sliding bracket is designed for use on a rectangular shower bar kit. Suitable for standard shower heads, shower clamps for hand held shower heads with standard connector. Fully adjustable: just press the button to adjust the height of the brackets on rail and release to tighten in place. Easy to install, simple to use. To fit 18mm width, 30mm length. Dimensions: 11.8 x 4 x 2.3 cm. Please measure the diameter of the rail before purchasing. And if there is any problem, please feel free to . Notes: Because the measurements are taken by hand, the sizes shown may vary by 1-3mm. Please make sure you do not mind before you bid. The actual color of the item may vary from the color of the photos depending on your monitor's display settings. Thank you for your understanding.