Model NO. UP6SC Standard Frequency 2500Hz Max.Output Sound Level Gain 42 ± 5dB Highest Sound Pressure Level for Input SPL 90dB 119 ± 5dB Equivalent Input Noise Level Below 19dB Battery Current Max 1mA Total Harmonic Distortion Value of Reality 1600Hz: below 3%;800Hz: below 4%; 500Hz: below 4% Continuous Use 180 hours per charge Battery Type Button size PR-41 battery Operating Temperature / Humidity +10? ~ +40? / 30% ~ 85% RH Storage Temperature / Humidity -10? ~ +60? / 30%~85% RH Size 24.3(L) x 13.7(W) x 10.9(H) mm 65.0(L) x 46.5(W) x 16.5(H) mm Weight 2.2g (battery included)