Button rollers with buffer springs for 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 and wear-resistant nylon wheels.and high quality. Designed with wear-resistant pads, more durable to use.colour: silverMaterial: nylon + zinc alloy + stainless steelsize: 23mmPackage Contents:2 x Top Rollers2 x Bottom Rollers2 x Bumper Block1 set x ScrewsOnly 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.