... components and parts began early 1980.1)Items——membrane switch, keypad, membrane keypad, keyboard switch, switch panel, membrane panel, membrane overlay, membrane faceplate for ... the circuit layer, it can be metal(stainless steel) dome 5)Circuit layer——Available with LEDs in a variety of colors ... type—— 0.6 - 1.5mmh) Life expectancyh-1) Flat type——5,000,000 closures or moreh-2) Tactile type——1,000 ...