Our catalytic combustors consist of a durable, temperature-resistant ceramic composition that is extruded into a specific cell density, creating a honeycomb configuration. It is then cut to specified sizes and fired. The unit is then wash coated with alumina oxide for high surface area coating and precious metal support. Later a noble-metal catalyst, like Palladium, is applied. 90% Less Pollution. 90% Less Creosote.5.66'' round x 1.5'' 25 cells per square inch replacement catalytic combustor 5.66'' round x 1.5''