Pipes can be measured using the measuring reference surface with the V shaped groove. Imbedded shackle for carabiner use. Imbedded shackle for drop prevention cord use. Large shackle for speedy storing and retrieval. Triple strength super magnet! I deal for steal-frame work with magnet. (Noedymium magnet) SPECIFICATIONS ・Hardened extruded aluminium alloy ・Alumite clear painted finish ・Pipe measuring functionality ・With 1 magnet ・4-line acrylic vial SENSITIVITY / ACCURACY Sensitivity 0.50mm/m=0.0286˚ Accuracy within ±1.00mm/m±0.0573˚