Slot diameter: 0.75-0.99 inches: The suction cup shower head holder with adjustable slot to hold the existing shower head. Suitable for shower hose bottom diameter between 18-23mm. Not suitable for smaller shower hose diameter >= 23mm. It is recommended to measure the size before purchasing. No drilling and easy to install: You can install the suction cup adjustable shower head holder in 1 second. No drilling or screws required. Stable, waterproof and rustproof, the hand held shower head holder will not damage your wall and leave marks after removal. Waterproof Material: The suction cup shower head holder is made of plastic Industrial grade ABS. Waterproof, rust and corrosion resistant. Sturdy enough for easy use in wet bathrooms for a long time. Adjustable Angle and Height: Swivel design is convenient to adjust the angle of the shower head up to 70 degrees. Removable and replaceable suction cup. You can place your shower head or bidet sprayer wherever you need it. For a high or low position, inside or outside the tub. Suitable for your wife, kids or parents who can't reach the shower head. Tips for use: This powerful shower head wall mount works best for non-porous, smooth surfaces such such as glass, mirror, ceramic tile, polished metal, plastic panels, etc. The suction cup will not work on a bumpy or uneven surface.