Button rollers with buffer springs for firm installation. Suitable for flat sliding shower doors and curved sliding shower doors. The top roller has no buffer spring, you can adjust the position of the wheel by adjusting the screw. Made of heavy-duty zinc alloy brackets, stainless steel smooth ball bearings and wear-resistant nylon wheels. 100% brand new and high quality. Designed with wear-resistant pads, more durable to use. colour: silver Material: nylon + zinc alloy + stainless steel size: 23mm Package Contents: 2 x Top Rollers 2 x Bottom Rollers 2 x Bumper Block 1 set x Screws Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.