Cute Acorns! They mix well with my Oak Leaves (in another listing.)
The last pic has the mm numbers next to them. The large is not pictured. I include the pic with the oak leaves so you can visualize the scale together.

Choose:
1/8" (3mm) without internal lines.
1/4” (6mm) with or without internal lines.
3/8” (9mm) with or without internal lines.
1/2” (12mm) with or without internal lines.
All but the 3mm are on round shanks a bit less than 3" long. The 3mm is on a 3/16" square shank, so it's easier to see.
These are generally easy stampers. For the smaller ones, be sure to use a smaller hammer.

Hardened and then tempered tool steel.
These are all made by me. There may be slight variations, but they will be pretty darn close to what's pictured.
Only the stamps mentioned are included. Other stamps or items pictured not included.