Futures Definition
Futures are a legal contract between you and an exchange to buy/sell a precise quantity, of a specific underlying asset (such as crude oil, currencies, grains etc.), at a precise date, to be delivered to a precise location.
Risk Profile of Futures
In futures contracts, because you are buying from and selling to an exchange, the counterparty risk is eliminated because you are dealing directly with an exchange and not a random person on the street.
Contract Specifications
Futures contracts are standardized & traded every day on an exchange so you they are very liquid and if you want to get out of one, you can easily sell it to someone else.
The exchange is responsible for determining what quantity of the underlying asset will be contained in one contract. Most crude oil futures contracts are standardized for 1,000 barrels of oil per contract.
The exchange is also responsible for specifying where the underlying will be delivered to, and when the delivery date is near; trading stops for that specific contract.
Some exchanges even allow you enter into mini contracts for a lesser quantity of the underlying asset, and this is to make it affordable to most investors. This is why we have things like the e-mini-S&P 500 contract.
Contract Nomenclature