Hoto Instruments NS-601 Handheld LED Stroboscope w/charger & rechargeable batteries High efficiency LED solid-state light source Extended battery life of 8 hours continuous use at 6,000 fpm/rpm, includes rechargeable batteries Highly stable drift free operation, auto wide measuring range, up to 120,000 fpm/rpm Push button operation with x2 and 2 buttons for quick adjustment Store up to 10 flash rates in memory for records or quick retests