That’s a Steel Letter Punch Set / Metal Stamping Set
What it’s used for:
Stamping letters into metal, leather, plastic, and other hard materials. You line up the punch, hit it with a hammer, and it leaves a permanent impression.
Key details from your photo:
1. Set: Full A-Z alphabet in a black plastic holder
2. Material: Hardened steel punches
3. Design: Each punch has one reversed letter on the tip. When you stamp it, it comes out right on the metal
4. Use: You need a hammer + solid surface like a vise or anvil