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 adjustable suction cup 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 industrial grade ABS plastic. 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. How to use: This powerful wall mounted shower head holder works best for non-porous, smooth surfaces such as glass, mirror, ceramic tiles, polished metal, plastic panels, etc. The suction cup will not work on a bumpy or uneven surface.