HETA’s Scan-Line 900S or 900S with side windows, is the model for you if you’re looking for the most out of your stoves heating capabilities. The Scan-Line 900S models have therma stones, they store the heat as you are firing in your stove. In the combination with one of the three stone finishes Soapstone, Blackwood or Limestone, you will be heating your house for 10-12 hours after the fire has died out.