The Osburn 1100 Insert is designed for smaller stone fireplaces with a 45-degree back face, offering various configurations. Its firebox has a 2.5-inch depth for better ash accumulation and cleaner use. This insert includes a powerful blower and provides 45,000 BTU of heat. Key features: Model Number: OB01151 Chimney diameter: 6" Overall dimensions (H x W x D): 21 1/8" x 25 1/2" x 22 1/4" Maximum log length: 17" Minimum fireplace opening (H x W x D): 21 3/4" x 26" x 12 7/8" Shipping Weight: 297 lb (135 kg) Firebox volume: 1.5 cu. ft. Recommended heating area: 250 - 1,400 sq.ft. Average particulate emissions rate: 2.9 g/h Combustion Technology: Non-catalytic Maximum burn time: 6 hours Blower included: Yes