Jackson Safety #7 Curv-O-Mark Centering Head Pipe Marker (14776), Jumbo, Y-Head, Dial Bubble Protractor, Aluminum, 1 / Order 1 Jackson Safety #7 Curv O Mark Centering Head Pipe Marker (Jumbo) / Order; is a must-have on your list of pipe welding tools This pipe centering tool helps with setting center lines, establishing angles and marks for butt-ins, locating points inside pipes and tanks, laying out keyways and measuring declivity Jumbo #7 Model may be used on pipe 1" in diameter and larger; use it for pipes and tanks The CurvOMark center finder has a 4 inch Y-type head fitted with an adjustable dial bubble protractor (DSL) Use this manually operated Jackson Safety hardened centering pin with a small hammer or mallet to tap the pin in for effective pipe marking