... size: L600mm,Dia34mm U head size: 160*105*30*5mm Adjustable length: 400mmProduct advantages :1. The scaffolding U head is made ... head jack is adjustable from 30mm to 40mm for different building heights.4. Scaffolding head jack commonly used to support inside concrete ... . With high durability and strength,u head jack provides stable support for large heavy structures such as stage,tunnel,bridge and ...