That’s a 12" Pipe Wrench
You can see 12" stamped on the jaw in the picture.
What it’s used for:
It’s used by plumbers and pipe fitters to grip, tighten, and loosen round pipes and fittings.
How it works:
1. Serrated jaws - The sharp teeth bite into pipes so it doesn’t slip
2. Adjustable - You can open/close the jaw to fit different pipe sizes
3. Long handle - Gives you leverage to turn heavy pipes with more force