Type EM-60B is a sub-miniature omni-directional electret condenser microphone only 9.8mm diameter & 7mm thick. Specifications Response Omni-directional Frequency response 50 Hz to 13k Hz Sensitivity 60d B plusmn 3d B 0d B 1 Vmicrobar at 1k Hz Vcc 4.5V Rl 1k Omega Impedance 1k Omega maximum SN ratio 40d B Sound pressure level 120d B maximum Power supply 1.5V to 10 Vdc Recommended voltage 4.5V optimum performance Current drain 0.4m A