EB Flat Bottom Side Brake Casters Wheel material: Elastic rubber tread + plastic wheel core, electrical insulation, chemical resistance, impact elasticity, acid and alkali resistance, Caster Wheel Platform suitable for electrical equipment industry, trolley industry, toolbox, Caster Wheel Adapters, etc. Tread hardness: 70 (±5) SHORE A Temperature range: -50~80°C" Wheel diameter: 3"-5" Load capacity: 70-135kg Flat bottom side brake casters, pressed rigid wheel frame, ball bearing Wheel Material: Elastic rubber with PP core Housing made of pressed steel, zinc plating, flat plate swivel caster with side brake.