Operation Mode: Stud, Stud Deep, AC, Metal, Indication: LCD ?4 modes 7 grades in stud mode AC indicator CAL indicator Low Battery indicator LED ?LED at center top of the unit lights when at the nearest distance to the stud Buzzer: sound indicate Auto Balance Sensitivity: AC: ≥8cm (110～220V) Metal: ≥6cm (for iron of dia 8mm，15cm long) Stud: ≥2.5cm (plasterboard) Deep Stud: ≥3cm (plasterboard) One 9V battery required （not supplied）