First, use your nose to smell whether there is an odor. The normal PVC material will have a little mellow smell, which is almost not smelled.

Second, wrap the sealing strip as tightly as possible on the profile and leave it at high temperature for a period of time (on the roof or in a sunny place). See whether the contact surface of the profile surface and the sealing strip is stained or discolored, whether the dust on the surface of the sealing strip is yellow (oil is easy to absorb soil), seepage oil, and whether the hands are dirty.

Third, some cheaper seal fillers will be a lot, so the surface will not be very shiny, and those that are cheap and not shiny are not desirable.

Fourth, depending on the specific gravity, how many meters can be produced per kilogram.