The dual TM (hmmm hmmm goooood)

WHAT YOU'LL NEED:

• A half a foot, and a foot long piece of clear plexiglass pipe, about 3 inches in diameter.
  A base to put the cylinders on.
• An aluminum or brass stem threaded on one end.
• A bowl that matches the threads on the stem
• A drill with a drill bit as big as the stem and a 1/4 inch drillbit (for making the carb hole)
  A drillbit the width of the plastic tubing.
  A piece of plastic tubing between a 1/4 and a 1/2 inch thick
  A plastic cap to cover the first cylinder tightly (needs to form a seal)
• Clear silicone caulk.

Attach hose through the top of the cap into the first cylinder (IMPORTANT: hose end should be ABOVE the water line). The other end of the hose, which goes in the second cylinder,r should be submerged under the water. Make sure the cap on the first cylinder forms a very tight seal!

HOW IT WORKS:
Load the first chamber boiling water and the second chamber with ice water.
Use normally, like a standard cylinder bong.

Why the boiling hot water? Wouldn't tap water work as well?

Very nice ... Hot water is better because its easily dissolve the tar and other harmful materials and with next cold water you can smoke a nice cold ppure THC !!!