tape from speaker to charging port board

just watched the video on HTC Desire 620 Touch Screen Glass Digitizer Replacement. Just after Disconnect the LCD flex cable, a peace of tape is removed from the ( i think ) the speaker and the charging port board. I have lost that piece of tape i do not know what it is called or made from, Can some one tell me what it is for what it is called and where i can get a new one.