Cant be positive, but from what I see it is a 1/6th barrel. They are 5.1 gallons and I use them quite a bit for kegging. You will need a sanke coupler
(verify type), faucet (cobra tap or faucet & shank
), co2 tank, regulator, beverage & gas line, and misc connectors. If you are going to get into kegging I use these tailpieces
on my coupler so I can easily change between sanke kegs and corny kegs with quick disconnects. You need to take out the spiral retaining ring to get the spear out of the keg
, make sure it is not pressurized. Then you can clean keg by by putting in a cleaner like PBW or oxyclean, sanitize, fill with beer, reassemble, purge air out and you are ready. No special tools are needed and with a little practice you will be able to disassemble and or reassemble in less then a minute.