Pond tubing from the home depot. 5/8 inside diameter X 3/4 outside diameter. This has worked great for me. Heat up the pond tubing in boiling water and slip it on. I tied a piece of small wire to one end of the chain ran it through the tubing and tied it to something substantial then I pulled the tubing over the chain with pot holders on my hand.

http://www.orderoutdoors.com/store_c...ct=Heat+Shrink

what Bow27 said. This is exactly what I did, exactly the same tubing. Use 6 foot for each chain and you're in business. dont forget, you need to remove the plastic bushings and file down the burrs some, an you're good to go. Just drill the holes out or use a soldering iron to melt them. Put the holes in the same locations as the stuff you remove...

Last time I needed it I got it from the link below. Order a couple sets. Make sure you get it for the right API.

http://www.orderoutdoors.com/index.asp

OR.... http://outdoorsupply.com/