UniquExceptional UHMD Hand-Held Security Metal Detector (Black) Highly Sensitive: Can detect a hand gun from 11 inches away, a pen knife from 6 inches away, and a razor blade from 4 inches away. Adjustable Sensitivity: The sensitivity can be adjusted with the turn of a switch. Two Indicators : You can choose either an audible tone or vibration Holster Included: For easy carrying a holster with belt loop is included. Optional Rechargeable Battery Jack: The unit is powered by either a standard or rechargeable 9-volt battery.(Search Amazon ASIN B00DL2P32Y for BATTERY CHARGER)