Heavy Duty Material :Ball bearing drawer slides work harden cold rolled steel with zinc plated finish will give you precise thickness and smooth surface.Bearing capacity up to 500 lb per pair. Anti Rust and Ant Corrosion :The electroplated layer can prevent direct contact between the air and the track steel plate, thereby resisting oxidation and corrosion. Easy to Install and Industrial DIY :3-Fold Full Extension,Side Mount.The slide rail can NOT be disassembled for installation.Suitable for Goods shelf,Mechanical Cabinets,Industry-used drawer,RV,Truck,Vending machine,etc. Package Includes :1 Pair x 20"Drawer Slides (Attention:The screws are Included.). Warm Tip :Our drawer slides are fitted with Type 304 stainless steel screws for easy installation.The metal pieces are sharp during installation.Please protect your hands.It is recommended to wear gloves for installation.You can contact us at any time if you have any questions,we are always there.Good life.