The Dupondius denomination
The dupondius (Latin two-pounder) was a brass coin used during the Roman Empire and Roman Republic valued at 2 aes (1/2 of a sestertius or 1/8 of a denarius).

The dupondius was introduced during the Roman Republic as a large bronze cast coin, although even at introduction it weighed less than 2 pounds. The initial coins featured the bust of Roma on the obverse and a six-spoked wheel on the reverse.

With the coinage reform of Augustus in about 23 BC, the sestertius and dupondius were produced in a golden colored copper-alloy called orichalcum (brass).

The dupondius was normally further distinguished from the similarly sized as with the addition of a radiate crown to the bust of the emperor in 66 AD during the reign of Nero.
Dupondius

(1) Antonia 42 AD
Obverse: ANTONIA AVGVSTA, draped bust right
Reverse: TI CLAVDIVS CAESAR AVG P M TR P IMP S-C, Claudius, togate, standing left, holding simpulum
Ref: Cohen 6, RCV 1903
(2) Antoninus Pius 157-158 AD
Obverse: radiate head right; ANTONINVS AVG__PIVS P P TR P XXI
Reverse: distyle shrine with arched roof containing statue of the Genius of the Senate, togate, raising hand, holding eagle-tipped scepter, standing on pedestal; COS__IIII / S C
Ref: RIC 989
(3) Augustus 15-14 BC
Obverse: AVGVSTVS TRIBVNIC POTEST, Inscription in three lines within oak wreath
Reverse: CN PISO CN F IIIVIR AAAFF, Inscription around large SC
Ref: RIC I (2nd Ed.) 381
(4) Augustus 18 B.C.
Obverse: AVGVSTVS TRIBVNIC POTEST Legend in oak wreath
Reverse: C . ASINIVS IIIVIR A A A F F around S C
Ref: c.f. RIC 372
(5) Clodius Albinus 194-195 AD
Obverse: bare head right; D CL SEPT AL_BIN CAES
Reverse: Saeculum Frugiferum standing left, holding caduceus with grain ears and trident; SAECVLO FRVGIFERO COS II / S__C
Ref: RIC IVa, 61 (C. 72); BMC V, 549 (Pl...
(6) Crispina 180-182 AD
Obverse: draped bust right; CRISPINA__AVGVSTA
Reverse: Juno standing left holding scepter and patera; IVNO LV_CINA / S__C
Ref: RIC III 680, Cohen 24, BMCRE IV 433...
(7) Faustina II 147-150 AD
Obverse: draped bust right; FAVSTINAE AVG__PII AVG FIL
Reverse: Pudicitia seated left, pulling veil and holding scepter; PVDIC_ITIA / S C
Ref: RIC 1404b, Cohen 187, BMC 2159
(8) Germanicus 37-41 AD
Obverse: GERMANICVS CAESAR, Germanicus, bare-headed and cloaked, standing in quadriga, right, holding eagle tipped scepter
Reverse: SIGNIS RECEPT DEVICTIS GERM S C, Germanicus bare-headed and cuirassed, right, with tunic standing, left, right hand raised and left holding aquila
Ref: RIC I (2nd Ed.) Gaius 57
(9) Hadrian 119-121 AD
Obverse: radiate bust right, draped shoulder, bare chest; IMP CAESAR TRAIANVS HADRIANVS AVG P M TR P COS III
Reverse: Salus-Fortuna standing left, stepping on globe, holding patera and rudder; SALVS P_VBLICA / S__C
Ref: RIC II 604a, BMCRE III 1237, Cohen ...
(10) Marcus Aurelius 176-177 AD
Obverse: [M ANTONI]NVS AVG GERM SARM TR P XXXI, Radiate bust right
Reverse: [IMP VIII COS III P P] PAX AETERNA AVG, Pax standing l., holding cornucopiae and setting fire to a pile of arms, S - C in fields
Ref: RIC3 1203
(11) Nero 54-68 AD
Obverse: NERO CLAVD CAESAR AVG GER P M TR P IMP P P, laureate head left
Reverse: SECVRITAS AVGVSTI S-C, II in ex, Securitas seated right, holding veil above her head, altar at feet right.
Ref: RIC 407
(12) Tiberius 19-21 AD
Obverse: TI CAESAR DIVI AVGVSTI F AVGVSTVS, Head of Tiberius facing right, wearing laurel wreath
Reverse: PONT MAXIM COS III IMP VII TR POT XXI, Upright caduceus between two crossed cornucopias framing two crossed branches
Ref: RIC I (Second Edition) Tiberius 89,...
(13) Tiberius 19-21 AD
Obverse: TI·CAESAR·DIVI·AVGVSTI·F·AVGVSTVS, Head of Tiberius facing right, wearing laurel wreath
Reverse: Blundered Inscription, Caduceus between crossed cornucopias
Ref: RIC I (2nd Ed.) Tiberius 89-90; RPC...
(14) Trajan 116-117
Obverse: IMP CAES NER TRAIANO OPTIMO AVG GER DAC PARTHICO P M TR P COS VI P P, Radiate draped bust right
Reverse: SENATVS POPVLVSQVE ROMANVS, Trajan advancing right with head turned left, between two trophies; SC below
Ref: RIC 676
(15) Vespasian 77-78 A.D.
Obverse: IMP CAES VESPASIAN AVG COS VIII P P, laureate bust right
Reverse: FORTVNAE REDVCI, Fortuna standing left holding rudder and cornucopiae, S-C across fields
Ref: RIC 1215
(16) Vespasian 76 AD
Obverse: Radiate head right; IMP CAES VESP AVG P M T P COS VII / S__C
Reverse: Felicitas holding caduceus and cornucopiae; FELICITAS__PVBLICA
Ref: RIC 886; Cohen 488
(17) Vespasian 71 AD
Obverse: Radiate head right; IMP CAES VESPASIAN AVG COS III
Reverse: Roma left seated on cuirass, holding wreath and parazonium shield and helmet to the right; ROMA / S C
Ref: RIC II, part 1, 277
(18) Vespasian AD 74
Obverse: IMP CAESAR VESPASIAN AVG, laureate head right
Reverse: PON MAX TR POT P P COS V CENS, winged caduceus between crossed cornucopiae
Ref: RIC² 756; RPC 1982