Our new Perlick kegerator can hold two small (7.75 gallon, 1/4 bbl, pony keg, half-keg, whatever you want to call them) kegs, one big (15.5 gallon, 1/2 bbl, full keg) and one small keg, four Cornelius kegs or some combinations of those. Local breweries usually sell their beer in the small kegs but they don’t always have them on-hand since they’re not as popular as big kegs. But many will fill Cornelius kegs that home brewers use. So I can take my kegs to them and have them fill them up with any of their beers and not have to wait until they get a small keg back from a customer. I can also fit 2 Cornelius kegs on each side for 10 gallons on each side rather than one 7.75-gallon keg, so I can have a cold spare keg ready when one runs out.