The Cloutank M3 is the newest design for use with dry herbs. Made of medical grade steel and Pyrex Glass.  The unique design allows for you to press down on the mouth piece to rearrange the herbs without removing the tank. This helps burn all the product in the tank.  The other nice feature is when you remove the tank and press down it cleans the tank for you. Two replacement heads and instructions are included in the kit. Extra replacement heads are available.  This is the best design we've seen on the market.