The Tetrobol denomination
A Tetrobol is an ancient Greek denomination worth 4 obols - 2/3rds of a drachm.

It was struck in both bronze and silver.
Tetrobol
(1) Histiaia
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An AR Tetrobol struck c. 267-146 BC in Histiaia
Obverse: Head of nymph Histiaia right with wine-wreath

Reverse: Nymph Histiaia seated right on stern of galley, holding stylis; ornate apluster; IΣTI_AIEΩN, trident below

Diameter: 13.5 mm
Die Orientation: -
Weight: 2.3 g
No notes for this coin
BMC Central p. 129, 52; SGCV I 2498 var.
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An AR Tetrobol struck c. 187-168 BC in Pella | Amphipolis
Obverse: head of Maenad right wreathed with vine leaves and grapes, wearing necklace and earrings

Reverse: stern of galley right, star above; MAKE / ΔONΩN, M?

Diameter: 15 mm
Die Orientation: -
Weight: 2 g
No notes for this coin
SGCV I 1384, SNG Cop 1292
(3) Phaselis
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An AR Tetrobol struck c. 500-440 BC in Phaselis
Obverse: Prow of galley right; uncertain controlmark below

Reverse: Stern of galley left; ΦAΣ

Diameter: 14 mm
Die Orientation: -
Weight: 3.4 g
No notes for this coin
SNG von Aulock-; Cf Heipp-Tamer 72
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An AR Tetrobol struck 323-315 BC in Amphipolis
Obverse: head of Apollo wearing tainia right

Reverse: horseman riding right; ΦIΛIΠΠOY, M in wreath

Diameter: 13.5 mm
Die Orientation: -
Weight: 2.52 g
Struck by Philip III in the name of Philip II
Le Rider pl. 45, 33; SNG ANS 625-7; SNG Alpha Bank 300
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An AE Tetrobol struck 180-170 BC in Alexandria
Obverse: Wreathed head of Isis to right

Reverse: Eagle standing to left on thunderbolt; ΒΑΣΙΛΕΩΣ ΠΤΟΛΕΜΑΙΟΥ around, monogram to left

Diameter: 26 mm
Die Orientation: 11 H
Weight: 16.03 g
No notes for this coin
Svoronos 1384; SNG Copenhagen 279-87
(6) Rome | Histiaia
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An AR Tetrobol struck c. 168 BC in Military Mint
Obverse: head of Histiaia right with wine-wreath

Reverse: nymph Histiaia seated right on stern of galley, holding stylis; ornate apluster; IΣTI_AIEΩN, crescent below

Diameter: 13 mm
Die Orientation: -
Weight: 1.74 g
Sear notes crude Histiaia imitations seem to have been struck in Macedonia just prior to the Roman victory in 168 BC. Roman military mints sometimes struck imitative types to make local payments.
See SGCV I p. 233 note following #2498