Bust of Chastana right with collar showing, wearing a satrapal cap, corrupt Greek inscription / Crescent on a three-arched hill over a wavy line, crescent in the left field, sun in the right field, two inscriptions one in Brahmi (RaJno KsaTraPaSa ChaStaNaSa and one in Kharoshti (RaNo KsaHaRaTaSa ChaThaNaSa). 16mm, 1.75 grams. Rajgor "The Studies in the Coinage of the Western Kshatraps" #197-203 or similar.
The coin is actually quite a bit nicer than the photo, with nice surfaces and a good portrait. Chastana was the founder of the Western Satraps' Kingdom and the founder of the Saka Era (Vikrama Samvat era), which is still used in India and in some other regions. Chastana ruled as Satrap until the fall of Nahapana in ca.100 AD, and after that as Mahakshatrapa ("Great Satrap"). The coins of Chastana are rare.