These 23mm sliding shower door rollers are suitable for both flat and curved doors, constructed with heavy duty zinc alloy bracket and wear-resistant nylon wheels for smooth and silent sliding. The top rollers can be adjusted through tweaking screws and button rollers have buffer springs for secure mounting. With high rolling capacity, these rollers ensure long service life and are backed by quality guarantee. Features 1. Suitable for both flat sliding shower doors and curved sliding shower doors 2. Top rollers have no buffer spring, you can adjust the wheels position through tweaking screws. Button rollers with buffer springs for a secure mounting 3. Strong structure, high rolling capacity for smooth and silent sliding, long service life. 4. Constructed out of heavy duty zinc alloy bracket, smooth ball bearing and wear-resisting nylon wheels. 5. Quality Guarantee. We have faith in our product and always back it up with trustful customer service, please reach out to us if you have any questions or problems about our products. Specification Material: Plastic, Metal Color: See Photo Package Includes: 2 x Top Roller 2 x Button Roller