Made of high-quality plastic, high processing durability, good wear resistance, smooth enough to prevent vacuum scratching the floor, dirt-resistant, quiet wheels, and no noise. a flat-blade screwdriver to push up the old , and then install the new in the groove. (Please note: these are smaller front wheels, not larger rear wheels.) with NV350 NV352 NV355 NV356E NV500 NV501 and other general models Installation Instructions : a flat-blade screwdriver to push the old upwards, and then put the new into the groove. Product name: vacuum floor brush small wheels colour:gray material:plastic Package Contents: 1 pair x wheels Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.