That’s a Scaffolding U-Head Jack / Adjustable Prop Jack
What it is:
• Name: U-Head Jack or Scaffold Adjustable U-Head
• Material: Galvanized steel - that’s why it has that silver/greenish zinc coating
• Parts:
1. U-head on top - The U-shaped steel plate that holds timber, beams, or formwork
2. Threaded rod - For height adjustment
3. Adjustable nut/collar - The 4-wing nut you turn to raise/lower it
What it’s used for:
This goes on top of scaffolding or props to support formwork for concrete slabs and beams.