Dear Sir: 15 inch gold grain pinpointer has been designed and developed to meet the demands for underwater 10 feet treasure hunting. ( 12PCs USD65.00/PC DHL Free Shipping ) It also features a lightweight, rugged, ergonomic design. A clear, concise control board provides an easy opration system The probe dia. only 0.5 inch ( 12mm ) it can easily push into all types of soil or sand and moving no difficult Specification: Communicates with: 1. buzzer alarm 2. LED light ( green power, red warning ) 3. Vibration alarm Over lenght: 15 inch (380 mm) Sensitivity adjusting Control board F - flashlight power ON/OFF C - charger DC hole S - sensitivity adjustment B - Light brightness adjustment Detection sensitivity: ------------------------------------------------- in water diameter detecting deapth silver grain 2mm (0.08 inch) 0.12 inch (3 mm) silver coin 25mm (0.98 inch) 2 inch (50mm) gold grain 3mm (0.08 inch) 0.04 inch ( 1mm) gold coin 25mm (0.98 inch) 1.2 inch (30mm) ------------------------------------------------- metalprobe photo .jpg in attachment B.Regards Mike Metal Probe Factory www.metalprobe.com