Quantity: 2 Sets Of Sliding Door Wheel Sets, Which Can Form Two Pulleys.High Quality Materials: The Wheel Frame Is Made Of Stainless Steel Plate, And The Pulley Is Made Of Copper Alloy. The Thickness Of The Thickened Plate Can Be Up To 1.5 Mm. The Material Is Thick And Difficult To Deform. It Can Be Used In A Humid Environment, It Is Durable, Corrosion Resistant And Rust Resistant. Stable: The Bottom Wheel Uses Smooth Bearing, Which Is More Stable And Heavier. The Concave Wheel Design Is More Uniform, The Bearing Shaft Is Smooth And Round, And The Sliding Has No Scratches.Belt Pulley Design: Adopt The Latest Concave Pulley Design. Each Activity Can Have Its Own Cleaning Effect, Eliminate Dust And Be More Durable.Quick Disassembly: Quick Assembly Button, The Upper Guide Wheel Adopts Copper Button, The Retractable Upper Wheel Is Convenient For Mounting The Door Panel. Cylindrical Catheter, Horizontal Rotation Structure, Smooth Sliding Without Jamming.