I beleave it's a 3/8" flare connection. Check in DIY for the threads that talk about beer line cleaners, they use a ball lock connection for those setups.
Something is always fermenting....
"It's Bahl Hornin'"
Kegged: Sour Saison, Pale Ale, Aggie Ale, Firestone DBA, De Koninck Blonde
Bottled: Belgian Quad (Grand Reserve), Derangement (Belgian Dark Strong)
On Deck: Pliny the Younger