Feature: The caster will move smoothly in all directions without making noise or scratches and marks on the floor. The caster can bear a load of no more than 5 kilograms, which can easily complete the heavy work. Flexible design: Ball-type pulley can rotate and slide 360 degrees at will. These rotating wheels are placed at the bottom of the storage box, making them time-saving and convenient to move. Specification: Material: ABS, stainless steel ball Size: 1.45 x 1.45 inch/ 37 x 37 mm Color: White Note: Manual measurement, please allow little size errors.