the Fleta1. Double Locking Mechanism: Double locking casters lock both the wheel and the swivel bearing, which is essential for safety and perfect for easily positioning your equipment in any desired area 2.Good Wear Resistance: Swivel casters rotate 360 degrees, allowing for rotating mating equipment, supporting heavy duty use 3.Smooth and Quiet: These wheels made of non-marking polyurethane rubber, with brakes, bring virtually no noise to your comfortable life and will not scratch any hardwood floor, very quiet operation, absorbs shock and vibration 4.Universal Use: The wheels can be used for a multitude of applications, including flight cases, instrument cases, display/exhibition equipment, trolleys, tool boxes, light machinery, equipment stands, mobile workstations, speakers, cabinets, stands, amps, electrical enclosures, furniture, etc. Features: 360 degree rotation. Smooth & Quiet & Sturdy. HEAVY DUTY Total locking brake locks both wheel and swivel. Capacity: 50kg Ball Bearings: Double ball bearings Brand New: 100% Specifications: Bracket: High quality steel - galvanizing Wheel material: polyurethane Bearing: Double steel ball bearing Wheel diameter: 3 inches Wheel width: 21mm Installation height: 90mm Installation size: 65*65 mm Installation hole distance: 45mm Installation hole size: 8mm screws not included