Performance and features an easy to operate, with a holster, easy to carry 2, with charging function, charging time is 4-6 hours (charger sold separately) 3, when the voltage is not enough, the light does not shine or until the alarm 4, light and sound vibration alarm prompted the dual mode 5, the first use of automatic reset switch to switch the sensitivity, enabling large items that can be detected (excluding small items), but also can detect small metal objects 6, with a sensitivity transfer function 7, which is a one of the most popular models, can be applied to any field. The education sector is currently the most used a handheld. Technical Specifications Dimensions: Length 410mmx85x45mm Package Size: 44.5cm * 26.5cm * 52cm Weight: 25 / box, 13.3 kg / box Power supply: 6F22ND 9V battery (alkaline battery, rechargeable battery) Alarm modes: sound (shock ) and light alarm simultaneously