Pipes can be measured using the measuring reference surface with the V shaped groove No need for screwdrivers in battery replacement. Easy open/close with a coin. Large shackle for speedy storing and retrieval. Being phosphorescent, the device draws on light from well-lit places to emit light for a few minutes in darker applications Imbedded shackle for carabineer use Imbedded shackle for drop prevention cord use Triple strength super magnet! Convenient when working with steel framing etc. SPECIFICATIONS Polycarbonate resin Hardened extruded Aluminium alloy Alumite clear painted finish Pipe measuring capable Magnet: 1 4-line acrylic l air bubble tubes Lithium CR2032 battery x 1 SENSITIVITY / ACCURACY Sensitivity 0.50mm/m=0.0286˚ Accuracy: Within ±1.00mm/m±0.0573˚