NDH-A High Accuracy Hand Held Needle Detector Purpose Designed for small products detection or exact locating. Specifications Detection method: Magnetic induction Detection sensitivity:Lo:20-30mm Hi-30-40mm With an iron setting pin of Φ 0.7mm,length 25mm,detection is possible within following renges; Detection adjustment: Lo-Hi2steps Detection width: 50*25mm Alarm method: Buzzer,Lamp Power source: 1.5V battery*2(AA) Dimension: 160mm(L)*55mm(W)*45mm(H) Weight: Appr200g