Regency's medium wood stove comes as a hybrid or non catalyst models. The F2500 is the hybrid model with 83,000 BTU's and takes 18" wood both east and west or north and south. The non catalyst model (F2450) is exactly the same size, just with out the catalyst. Options include blower, pedestal, legs or the new wood stacker base. Heats up to 2,200 square feet.