[TriEmbed] Source for AAA heat shrink tubing?

[Ed Blackman]

Does anyone know a local, or cheap shipping, source for heat shrink 
tubing?  I need to replace a NiMH battery pack that is basically two 
AAAs heat shrinked together (similar to this, though not exactly: 
http://amzn.com/B008R7ABNO).  I have the replacement batteries working 
with masking tape holding it together, but would like have a better 
permanent solution.

I can find the tubing for cheap online, but the shipping makes it 
expensive since I only need a little.

I need tubing wide enough to accomodate 2 AAA batteries side by side, so 
21mm.

Thanks for any pointers.

-- 
Ed Blackman