This coin is an Akragas, Sicily, AR Didrachm, from circa 510-472 B.C.E. AK above and beneath sea-eagle standing right / Crab.
The Siege of Akragas took place in 406 BC in Sicily; the Carthaginian enterprise ultimately lasted a total of eight months. The Carthaginian army under Hannibal Mago[ besieged the Dorian Greek city of Akragas in retaliation for the Greek raids on Punic colonies in Sicily. The city managed to repel Carthaginian attacks until a relief army from Syracuse defeated part of the besieging Carthaginian army and lifted the siege of the city.
This coin is authenticated by Mr. Paul Karon, Professional Numismatist, and is guaranteed guide by Walker Christopher ltd.