The SESTERTIUS was the largest Roman Imperial Coin to be minted. This one is one of ANTONIUS PIUS A.D.138 to 161
The Reverse is ANNONA relating to the Annual Corn Supply to ROME The stands holding corn ears & a Cornucopia (horn of plenty) found with a T2 sens 75 Disc 15 Sounds 2+ & Ground grab
The stayed in use for quite a few years as shown by the wear on this coin probably 50 years or even more.