Overprint C has three types. This overprint was used on stamps Pofis / 57, 58 and 111 – 118.

Typ C I

The height of the overprint is 16,0 mm, the length 27,2 mm.
The height of the letters is 4,0 mm, the angle is 24º.
- The hook over S look a like a heart and is placed close to the S.
- The first K in CESKOSLOVENSKA is open.
- The third S in CESKOSLOVENSKA is laden at the top, not cut.
- The word POSTA and 1919 are hardly noticeably
displaced to the right compared to type II - The second 9 in 1919 is cut.
Typ C II
The height of the overprint is 16,0 mm, the length 27,5 mm.
The height of the letters is 4,0 mm, the angle is 22º.
- The hook over S look a like a heart and is placed close to the S. (almost same as type I)
- The first K in CESKOSLOVENSKA is closed.
- The third S in CESKOSLOVENSKA is cut.
- The word POSTA and 1919 are hardly noticeably displaced to the left compared to type I.
- The second 9 in 1919 is cut.
Typ III

The height of the overprint is 16,5 mm, the length 27,2 mm.
The height of the letters is 4,0 mm, the angle is 25º.
- The hook over S is angular and is placed higher and a little bit to the left.
- The first K in CESKOSLOVENSKA is closed (as type II).
- The third S in CESKOSLOVENSKA is same as type I.
- The word POSTA displaced to the right so the axle of T pass between S and L.
- The second 9 in 1919 is cut.