Specification: Surface Hardness: 3H Optical Clarity: 80 % Operating Temperature: -20癈 ~ 60癊ndurance Test strikes: Over 1 million Operating Voltage: DC5V Resistance: 200W ~ 900W Linearity< 1.5% Faceplate Surface: Anti-glare coating Operation Pressure: 15 ~ 70g Storage Temperature: -20'C ~ 70'C Message Noise: 5 m sec ~ 15 m sec Operating Current: 5mA ~ 25mA Isolation Resistance: 20MW DC25V