*Simple and convenient operation *Fairly low consumption of battery *Extremely high detecting speed *Extremely high accuracy and sensitivity *The battery management system continuously monitors the deficiency of power and voltage. *Most adapting to the man's hearing difference, it will generate different alarm tones depending on the size and distance of metal. *The alarm sound will last when finding metal and continuously lock its correct position. *The probe will give an alarm easily when a pin is 35mm to it. Product parameters: External dimensions:Length 395 mm*140 mm Product weight:20/box, 13 kg/box Unit gross weight:0.5 KG/1 PCS Working power supply:6F22ND 9 V battery (alkaline battery, Rechargeable battery) Alarm modes:Simultaneous sound and light alarm