New to DUROCK's offerings are now switch films! What makes these films different? They're composed of 2 layers, a bottom layer Heat Transfer Vinyl (HTV) and a top layer of Polycarbonate (PC). Very useful to decrease vibration & wobble. Of note, DUROCK suggests the HTV side should be placed on the bottom housing, and the PC side should be facing up towards the top housing. The HTV material is a matte color, while the PC material is transparent.