What is this device?

[admin]

http://www.ebay.co.uk/itm/281041441381

[Eoin]

It looks to me like a hand pump that needs no gas, you hand pump pressure into it using the second pump on it, it'd want to have a good filter on it.

[LordEoin]

I'm wondering what kind of keg it would fit...

[marceldesailly]

not meaning to sound facetious but its for a Hoff-stevens keg.

Best way to think of them is as a hybrid of kegs/cask.  It's an open-system keg, so it has a center valve on the top like a keg and a bunghole in the side so you can fill/clean it without any extra equipment. I looked at them a while a go as I had a contact who had them but decided it was too much hassle unless you get them mega cheap. The newer ones seem to be in plastic/rubber from what I've seen.

[LordEoin]

lol, that makes sense... figured it was the make of tap/pump.
Christmas has dumbed me down a few points...
Everything I read about them suggests they're more trouble than they're worth