In article . com,
says...
Hi guys, i am trying to find some water pipes and reducers on the net,
but i am struggling. I have a water chiller which has an 12mm internal
diameter(id). This must be attatched to a 6mm (id) imaging device which
is being cooled. So basically i need a 12mm - 6mm reducer and the
pipes. The pipes need to be like normal flexible hose pipes, but
preferably clear. The main thing is that they must be flexible so that
they can fit over the male connector of the chiller system. Does anyone
know the best way to do this and where i can get the pipes and
fittings??.


Aquarium suppliers, homebrew suppliers, model shops, motor factors?

http://www.brewathome.co.uk/cat/page21.htm

http://www.pumpsandspares.com/other-...hoseselect.htm

Or of course eBay: http://search.ebay.co.uk/_W0QQsassZsavemoney99

Rather than using 6mm and 12mm tubing you could just make a rubber bung
with 6mm ID and 12mm OD, attach that to the 6mm spigot, fit the 12mm
hose to it and secure with a jubilee clip.