King's bust facing right / Bull seated right, with Brahmi legend around (5 o'clock): Parama-bhagavata sri Skandagupta Kramaditya ("Overlord of Kings, Skandagupta Kramaditya, great devotee of Vishnu"). Struck somewhere in NW Maharashtra (Mumbai?) or just north of it. 11mm, 1.58 grams. Michael Mitchiner, Ancient & Classical World, 4881. 

This is the rare bull type of Skandagupta, a numismatic innovation started by him late in his reign, that replaced the normal Garuda symbol on reverse with a Nandi bull, a Shaivite symbol. "Bull" type coins were struck to a 1/2 karshapana standard (about 1.65 gram) and are lighter that the "Western" drachms struck to Western Kshatrapa standard of about 2.1 grams.