For colored tape, it is generally yellow and khaki. Pinch the sticky and quickly pull it apart, you can pull off the glue on one side, and you can see the purity and transparency of the original film. You can also look at the thickness of the glue. If no glue is pulled apart or pulled apart in dots, there are a lot of impurities in this glue, and the glue has no cohesion. The second is that the moisture is too much and has been volatilized. At this time, the initial adhesion of this tape has dropped very much, and the hand feel can be distinguished. In fact, there are many ways to distinguish between good and bad tape. As long as you pay more attention in your life, you can tell whether the tape is good or bad.