The Tetrassarion denomination
The tetrassarion was a bronze denomination worth 4 asses - assarion in Greek.

It was commonly struck by Roman Provincial mints, and was not struck to a standard weight but rather to some local standard. It was simply a coin worth 4 of the local basic coin denomination.
Tetrassarion
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An AE Tetrassarion struck 212-217 in Tyras
Obverse: ΑΥΤ ΚΑΙ Μ ΑΥΡ CЄΥΗΡΟC ΑΝΤΩΝΙΝΟ Laureate head of Caracalla to right

Reverse: ΤΥΡΑΝΩΝ Caracalla, holding spear in his right hand, riding to right

Diameter: 26 mm
Die Orientation: 7 H
Weight: 9.38 g
No notes for this coin
BMC -. SNG Copenhagen -. Zograph -
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An AE Tetrassarion struck 161-176 AD in Philippopolis
Obverse: draped bust right; ΦAVCTEINA__CEBACTH

Reverse: veiled Demeter standing half left, holding torch in each hand; ΦIΛIΠΠO_Π_OΛEITΩN

Diameter: -
Die Orientation: -
Weight: 9.6 g
No notes for this coin
Varbanov 886 (R5)
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An AE Tetrassarion struck 193-217 in Nicopolis ad Istrum
Obverse: IOVLIA DOMNA CE, draped bust right

Reverse: OOVONI TEPTVLLOV NIKOPOLITWN Julia on left standing right and Septimius Severus on right, standing left, facing each other clasping hands, PROC ICTRWN in exergue

Diameter: 27 mm
Die Orientation: -
Weight: 9.9 g
maybe HHJ plate coin?
Moushmov 1055, HHJ (2018) 8.17.34.2