A good caster will help you prevent costly floor repairs and forget the desk chair mats. And lockable casters let you prevent unwanted movements when you’re sitting, which is especially common (and annoying) on hard surfaces. Hirate Chair Casters with Brakes will meet your need. High quality polyurethane material will not to scratch or leave marks on any surface, protect your floor perfectly. There are 2 Standard Casters and 2 Casters with Single Locking Mechanism, you can fix your chair as you like! Features: 【2 PCS SINGLE LOCKABLE CASTER WHEEL】 --The brake locks the WHEELS ONLY and the swivel is still moveable -- With brake, effective to stop and fix the device and prevent it moving to hurt others. 【HIGH QUALITY MATERIAL】 -Made of high quality polyurethane, which is high mechanical strength, shock absorption and low-noise. 【SMOOTH & QUIET ROLLING】 -Two precise bearings and soft polyurethane ensure that you can slide and glide around in total silence with these swivel casters. Specification: *Stem Type: IMPERIAL SIZE *Stem Diameter:3/8" *Stud Length: 0.79"(20mm) *Wheel Type: Threaded Caster *Wheel Diameter: 2"(50mm) *Wheel Width:0.94" *Installing Height: 2.63" *Wheel Material: Polyurethane *Bracket: High quality steel - galvanizing *Double Bearing: Steel ball bearing *Total Load Capacity: 400 lbs Package Contains: 2 x 2" Stem Caster Wheels with SINGLE BRAKE 2 x 2" Standard Casters without brake 4 x 3/8"-16 Threaded Screw Inserts Hirate Heavy Duty 3/8" Threaded Caster Wheels Set of 4-A must have for DIY projects at home.