Adhesive Gel Pads These gel pads are made of hydrogel, self-explanatory to use, just tear off the two protecctive layers, then stick to the placement of your belt. SERVICE LIFE OF 30 Under normal circumstances, the gel pad has a service life of 30 , if you use and maintain it in the . When should replace it? When you find foreign matter or dirt on the gel pad, the gel pad surface is dried out or lost adhesion. replace it in time to avoid affecting the device's use. Precautions it attached to your skin, keep your skin clean and dry, then put on.After finished, keep in a sealed bag so that the gel pad not dry quickly. It might be not sticky enough after used for a few , you can put a few of water on it and out the water and wait 5-10 mins until the water absorbed completely. Since the gel sheet is a consumable item, exchange it for a new item if you feel it is exceeded for after . There are two pieces in one package. color:blue Material:hydrogel Package Contents: 40* 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.