The Diassarion denomination
The diassarion was a bronze denomination worth 2 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 2 of the local basic coin denomination.
An AE Diassarion struck 117-138 AD in Sparta
Obverse: laureate bust right, draped shoulder; ΑΥΤ{Ο} ΚΑΙ{СΑΡ} ΤΡΑΙ{Α} ΑΔΡΙΑΝΟС СΕΒ{ΑС}

Reverse: Dioscuri on horses right, holding spear and reins; ΛΑΚΕΔΑΙΜΟΝΙΩΝ

Diameter: 24 mm
Die Orientation: -
Weight: 9.6 g
The information with this coin from the Albert Reeves collection says that it was bought for £2 back in 1984 from S P Kitson who graded it as 'Poor'. We have nothing else to say about it except that we are asking the same price now as it was 34 years ago.
Grunauer group XXXVII, series 1-11; RPC online Volume III, 335
An AE Diassarion struck 251-253 AD in Isinda
Obverse: laureate, draped and cuirassed bust right from behind; AV KE Γ OVIΔ OVEΛ OVOΛOVCCANOI

Reverse: Tyche standing half left, holding rudder and cornucopia; ICINΔ_E_ΩN / AP_X·M

Diameter: 24 mm
Die Orientation: -
Weight: 9.7 g
M., archon
H. v. Aulock, Münzen und Städte Pisidiens I, 98 f., 913-923 Taf. 20 (stgl.); SNG v. Aulock 5047 (= 913); SNG Pfalz -; SNG France 1621 (= 922).