Safe for Hardwood Floors, Office Chair Casters Safe for all floors, hardwood, laminate and more easy rolling on the floor. Standard size.This black chair casters come with standard 0.4 inch (10mm) screws or standard stem (11mmx22mm) for most office chairs furniture, easy installation and the wheels made of plastic and nylon material, be quiet when rolling on the floor. Heavy duty, 5 pack supports 350 lbs making it the best replacement for your office or desk chair furniture. Smooth movement, swivel wheels is 360 degree rotatable.Roll smoothly and get you through any corner of the room.