Commonly used in the control panel, with stable performance and reliable operation, rich colors, simpleassembly and long life. （1） TEXTPLATE POLYDOME Force:1.5N-3N；（2）2.5N-4N ；（3）3.5N-5N ， Click ratio: 45％±15％ Dia. Of keys: 5, 5.5, 6, 6.5, 7, 7.5,8㎜, but D=6-7mm will be the best tactile feeling. (2) POLYDOME: common for Dia=5㎜ FORCE: 200+/-30g, Click ratio :40%~60%;return force:40g (3) Metal dome: common for Dia=4 & 5㎜ FORCE: 120~200g; Click:40%~60%;return force:40g