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 TIMES Under normal circumstances, the gel pad has a service life of 30 times, 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 is dried out or lost adhesion.please replace it in time to avoid affecting the device's use. Precautions Before it attached to your skin, please keep your skin clean and dry, then put them on.After finished, please keep them in a sealed bag so that the gel pad not dry quickly. It might be not sticky enough after used for a few times, you can put a few drops of water on it and smooth out the water and wait 5-10 mins until the water absorbed completely. Since the gel sheet is a consumable item, please exchange it for a item if you feel it is exceeded for after open. There are two pieces in one package. color:blue Material:hydrogel Package Contents: 40* patch 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.