What is specific about futures contracts?

Four things:

the commodity being sold

the amount of that commodity you'll get

the price per unit

and the settlement date

If you buy a CME copper futures contract...

the commodity is Grade 1 electrolytic copper cathodes, full plate or cut, conforming to ASTM specifications for this metal, and physically delivered

the amount is 25,000 pounds

the price is in cents per pound

and the settlement date depends on the contract you bought.