Johnson 40-6791 Machine Mountable 360-Degree Laser Detector with Clamp and Magnet This detector comes with a machine mountable detector clamp and magnet a NiHM rechargable battery pack Detecting range up to 650' and accuracy on fine plus or minus 3mm to plus or minus 25 mm and on coarse plus or minus 5mm to plus or minus 25mm Has a large 10" receiving window and a 360 receiving angle with a battery life per charge of aprox 40 hours Includes a limited 3 year warranty