STROBOSCOPE   FEATURES * Stroboscope use high intensity XENON tube. * LCD display with back light. * Stroboscope range : 100 to 15, 000 RPM. * External trigger for stroboscope. * DCV power supply via external AC/ DC adapter,  90-260 ACV/ DC adapter is the standard accessory. Recharge batteries * Build in battery compartment, power can use ( optional )  the DC 1.2 V Ni-MH recharge battery ( UM-1,  D size ) X 4 PCs, the recharge batteries and the battery charger are the optional accessories.