Pipes can be measured using the measuring reference surface with the V shaped groove. It is easy to read with lens. Precision is adjustable. 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 carabiner use. Imbedded shackle for drop pervention cord use. Triple strength super magnet! I deal for steal-frame work with magnet.(Noedymium magnet) Specfications ・Hardened extruded Aluminium alloy ・Alumite clear painted finish ・Pipe measuring functionality ・4-line acrylic horizontal vial with lens ・4-line acrylic vertical vial ・With 1 magnet SENSITIVITY / ACCURACY Sensitivity 0.50mm/m=0.0286˚ Accuracy: Within ±1.00mm/m±0.0573˚