I recently picked this coin up at an auction. I wasn't aware of Constantius I follis with Jupiter reverses. I already had two nice Hercules reverses from Siscia (163a and 165a). I actually found out that my collection is quite Contantius I heavy with more than 100 of his coins...
CONSTANTIUS I. CHLORUS. 305-306, Siscia.Follis. R.I.C. 179a.