okay, I have been trying a couple different kinds of tubes and here's
the ones that are of interest to ferret owners who want to watch ferret
tunnel fun.  as far as I can tell, there are approximately 3 kinds of
thickness.
 
a) ferret freeway style _vinyl_ clear hose.
these come in 20 ft length, and compresses to about 1.5 ft.  diameter
is 4 inches.  the wire is covered but they do rust if you wash the
tubes.  the vinyl is very thin, and does not stand up well to constant
scratching.  if you've got a ferret that likes to scratch in a tube,
these are not for you.  you can find them in at most online ferret
stores.  the super pet 8ft Flex-E-Funn-nel is the same thing with
plastic attachments for FerreTrail.
 
if you've got ferrets that don't dig in tunnels, you may want to try
these out.  they generally sell for about $20 us/cdn for 20ft.  if you
wish to buy them in bulk, Barb Hoult of the Alberta Ferret Society have a
contact where you can buy them cheaper in boxes of 9.  I've gone through
5-10 tubes in the past few years, after mending them with duct tape.  my
current four are such diligent diggers that I've given up on them.
 
b) dust collection PVC clear hose.
these are used in multiple areas, including dust collection for power
tools and can be found in wood crafting stores or stores that specializes
in selling hoses.  you can find them in diameters from 1.5" all the way
to 6".  the pvc is a fair bit thicker than the vinyl tubes, and the wire
coiling around the tube is quite thick as well.  you can sit on these
tubes and they won't collapse.  a 10ft length compresses to less than 30
inches.  they expand to about 7 ft after you unbox them, and then expand
slowly or you can stretch them out more.  they are pretty tough, I doubt
the average ferret would be able to tear it just by scratching
persistently.  I think you'll need to puncture it to make a tear.  wire
is covered, however, the one I got came a bit rusty.  I found I a spot
where the plastic covering the wire isn't secure.  it is not a hazard to
the ferrets, though.
 
I would recommend these for the most ferrets.  they are about double the
price of vinyl tubes, but will last you years instead of weeks.  they
also come with their own connection pieces of y joints and clamps to
secure.  the hose clamps are very useful.  you can buy them in 10, 25, 50
ft pieces, and the cardboard box mine are packed in makes a great toy as
well.  some places sell them by the foot.
 
in Canada - lee valley, item E
   http://www.leevalley.com/wood/page.aspx?c=1&p=51505&cat=1,42401&ap=1
in the us
   http://www.ducting.com/R_2_Clear.html
 
c)  polyurethane (pu) hoses.
its similar to pvc tubes, except thicker and stronger.  even the wire is
thicker.  you could probably jump on it and it'll be okay.  compresses
from 10ft to just under 3 ft.  I've had mine for a couple of months and
they've expanded to full length under room temperature.  resistant even
to ferret chewing.  the plastic covering the wire seems thicker.
 
in Canada - lee valley, item A  (about 2.5x the price of the pvc tubes
for a 10 ft length)
   http://www.leevalley.com/wood/page.aspx?c=1&p=51505&cat=1,42401&ap=1
in the us
   http://www.ducting.com/Flx_Thane_LD.html
   http://www.woodcraft.com/family.aspx?familyid=1780  (cheaper, and
have some cool hose fittings - thanx to Melanie Bordner for supplying
the site and making me realize pvc tubes aren't necessarily the widely
available ferret tubes)
 
notes: I'm not really sure of the difference between polyvinyl chloride
(pvc), or polyurethane (pu).  here's a chart I found on greenpeace's
website:
 
    http://archive.greenpeace.org/toxics/pvcdatabase/bad.html
 
some of the tubes I've seen say pu reinforced pvc.  based on greenpeace's
chart, apparently PVC isn't very environmentally friendly, and PU is only
slightly better, so I look to see if there are any polyethylene (PET)
tubes, as PET was recommended.  I found these:
 
    http://www.ducting.com/Mark_II.html
 
however, they are translucent, so you won't be able to see the ferrets
running through quite as well.  I may keep looking, but I did promise a
summary..
 
I'd recommend buying the 10ft tubes and look for various hose fittings to
make a great tunnel system.  another good reason to get the 10ft tubes is
because they come in a great cardboard box that my kids love (I now have
3 tubes and 3 boxes).  the pvc or pu also come in other sizes, if you
look at stores that specialize in selling tubes, so if you've got a kid
that won't fit in a 4" tube, you can find something for him/her still.
 
tubed out...
 
Selina, Clef, Popcorn, Sorin & Mochi
 
p.s.  both pvc and pu tubes survived the testing of 4 rambunctious kids
and 11 ferrets quite well.
[Posted in FML issue 5336]