It looks like there is an improved design of the Dampp-Chaser which
includes a humidistat and humidifier as well as the traditional
rod-shaped heater.  It's described on these web pages:

  http://www.dampp-chaser.com/componen.htm
  http://www.dampp-chaser.com/why1.htm
  http://www.dampp-chaser.com/inside.htm

Jody Kravitz