... and parts began early 1980.1)Items——membrane switch, keypad, membrane keypad, keyboard switch, switch panel, membrane panel, membrane overlay, membrane faceplate ... we are suggest that PET is the best choice.3) Surface——gloss & smooth ,velvet,matte & coarse finish, semi-gloss with ... moreh-2) Tactile type——1,000,000 closures or morej) Surface hardness——3H or more k) Operating temperature—— -40°C ~ + ...