See if there are defects from the outside, whether the tape reel is attached, the cutting has no hair edge, or whether the adhesive tape is smooth to see the adhesive tape material (there are many kinds of electrical insulation tape, not one by one to introduce the quality of the material, in most cases also have to see the use of the situation) and then see the glue, now most of the glue has evolved to the environment. The road is very important, if it is very harsh, the possibility of the secondary is larger (not all tape), it is the adhesive tape when it is used, and if the adhesive is torn down, there is no residual glue. If the glue is in the product, this is the fatal point of the secondary adhesive tape. The PVC material is basically the same, mainly the glue and the poor quality. After the tape is bandaged for a period of time, then unlock, you can see the glue and PVC material separation, looks sticky, very uncomfortable, and the quality of the tape will not be the problem.