The Jumbo Centring Head assists with the setting of centre lines, establishing accurate angles and marks for butt-ins, location points inside pipes and tanks, laying out keyways, and measuring declivity. The jumbo head model can be used on 1" diameter pipes and up. This tool consists of an 8" Y-type head attached to an adjustable dial bubble protractor (DSL.) A spring-loaded hardened centring pin feature on this head eliminates the need for a hammer. Just make the alignment and press the trigger.