Features of M type button: 1) Faceplate of M Screwing Type button: hairline stainless steel, Aluminum, stainless steel in golden color; 2) LED light of M Screwing Type button: red, green; 3) Braille: with Braille or without Braille ; 4) Cable: with cable/ without cable; 5)Rated Voltage: DC24V; 6)Rated current: 30mA; 7)Size of hole 49,78 8)M Screwing Type button Mainly for Schindler elevator