Tact switch is ultra-miniature

E-SWITCH Ultra-miniature tact switch measures 3mm x 2.6mm x 0.65mm and provides 100,000 cycle life expectancy and 2 gram force options. Devices specificatons include an electrical rating of 20mA 15Vdc; contact resistance of 500m-ohm (Max); insulation resistance of 100M-ohm (Minimum at 500Vdc); and a dielectric strength of 250Vac for 1 minute.

http://www.e-switch.com