Features: 1) Ultra-thin computers caps design, Aesthetic appearance 2) Durable structure, long life 3) Non-synchronous digital input, no affection to the other keyboard Specification: 1) Compatibility: IBM PC AT MAC 2) Button design: 19 bonds 3) Key trip: 3.0 +_0.3mm 4) Surcharging height: 0.25+_0.05mm 5) Maximum pressure: 55+_5g 6) Operating temperature: 0-55C 7) Key life: 800milliomon and above 8) Products size: 100*140*15mm 9) OS:windows 98SE/Me/2000/XP/Vista; Mac os 10.4above

http://olla.gr/usb-non-synchronous-notebook-computer-numeric-keyboard-with-19-keys/