That's a bomb suit, the most hardcore protective suit ever constructed. It's got armor in front, and padding in the back, so if the bomb you're trying to disable blows up on you and propels you backward, it'll cushion the blow against whatever your back slams into (in theory). And it's extremely heavy, so you can actually lose weight if you wear it and walk around in it long enough.
These things work very well against explosions caused by small amounts of plastic explosives:
https://www.google.com/books/edition/Bomb_Squad/ibCZAAAAQBAJ?hl=en&gbpv=0