Contact your brewery, draft beer supplier or wholesaler and they can help you with information about the connection type they use on the barrels.
The body of the keg coupling is made of nickel-plated bronze and the parts that come in kontakt with the beer are of stainless steel. Both connections are 1/2 inch. add with 1/2" tube barb connector or push-fit connection for connecting hose to gas and beverage and a silicone check valve for the gas connection.