All good posts above. I didn't notice whether anyone mentioned that the pin-lock kegs are slightly larger in diameter (25" tall x 8 1/2" dia) than ball-lock (22-23" tall x 9" dia). That can make a difference in how many you can fit in a particular fridge or freezer (height is usually easier to work around. I have ball-lock kegs and can fit four in my lagering fridge. If they were pin-lock, I'd only be able to fit three.