Kegerator is a refrigerator to cool kegs. They come in a variety of sizes that determine how many kegs can be stored and cooled together and different options like ones that include the tower at the top – this allows you to dispense with the keg inside, etc.
Junior kegerator would then mean, a kegerator meant for mini kegs. This category includes a complete system including the tower, faucet and a drip tray too.
Mini kegs are 2 litre Stainless steel kegs that can hold about 4 pints of beverage. You can fill them with beer or cold brew and place them in the kegerator to keep them ready whenever you want a drink.