1. Tear off the old tire on two wheels and clean the remaining glue on the steering wheel; 2. Notes: do not use AB glue and other hard plastic, you can use Wan Nengjiao, 100 plastic, neoprene 3. After finishing in plastic, over 5-8 minutes and then affixed the wheel, sent after 24-48 hours to use positive and negative distinction: the treadmill on the mop is divided into two parts, one on the ground (we call it positive) and the other on wheels (we call it the opposite) all in place of tire skin, we should pay attention to the positive and negative do not paste the anti. positive: from the outside, lines are vertical negative: from the outside, lines are horizontal lines positive resistance is small, the opposite resistance is greater, if posted against, it will be less wearable, the duration will be slightly short. Material: plastic colour:Black Package Contents: 2 * Caster Wheels Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.