battery.1x AA batteries (Not included) More attractive to the cat.It also could be used as laser presenter. Mini flashlight for indoor and outdoors daily use. Better for indoor use in dark and the optimal projection range is 3 m. There is no need to hold the button.Just push the button one time and it stay on. The funtion : Check the banknotes chaser the cats , illumination Size : 10*1.6*1.6cm Package include:1 pcs Cat toy