describe sliding door shower roller Our kit includes 8 shower door casters (4 upper and 4 lower double); each wheel has a diameter of 23 mm; they are suitable for glass with a thickness of 4 to 6 mm and a weight of 42 to 45 grams reliable material Each shower door roller is made of solid zinc alloy with a durable chrome finish; the wheels are made of durable plastic; all materials are high-end materials that are resistant to corrosion, rust and will not crack or crack over time degradation quick assembly These shower door rollers are quick and easy to install; there is a spring button on top of the bottom casters to differentiate them; once installed, our rollers allow your glass shower door to glide smoothly Practical spare parts Our replacement casters fit most showers, saunas, bathtubs or massage rooms; they allow you to easily and easily open and close your sliding doors for longer