This coin is not in RIC with an H in the left field, though the footnote for Rome 210 (#4) mentions this variant with H.
Maxentius
A.D. 308- 310
22x23mm 5.6g
IMP C MAXENTIVS P F AVG; laureate head right.
CONSERV VRB SVAE; Roma seated in hexastyle temple holding globe & sceptre, wreath in pediment; H in left field.
In ex. RBP
Cf. RIC VI Rome 210