Its a German party keg (fassanstich). It takes a type A coupler and has spear etc. It also has a spring loaded Bavarian style bung to give the option of tapping for a party - where is sits on a table. I've even got the wooden hammer to knock the tap (messingzapfhahn) in. I went for the Rhineland style zapfhahn instead of the Bavarian style (which you would see at Oktoberfest). When you tap it party-style, you put the little cap on the top to vent it. Obviously you want to go through the 10L in one session if you tap it this way. Unless of course you want to use it as a real ale cask and let the beer slowly oxidise (which is not my cup of tea).
Outside is special hard rubber/plastic compound that functions as insulation to keep it cool when sitting on the table, and for mechanical protection. Obviously its a stainless keg within.
You can get them from 10L up to 50L.
Will wait until I brew an alt to christen it (have Wyeast 1007 in the fridge). :beerbang: