AllerAir is proud to offer air purifiers that feature the deepest carbon beds on the market, with up to 40 different proprietary carbon blends. Their carbon beds are made up of actual granular pieces of carbon, not crushed carbon, and can be customized with between 4 pounds and 120 pounds of carbon to efficiently absorb any gasses, odors and chemicals. The lifespan of their carbon is far greater than many competitors, and has an unparalleled absorption capacity. AllerAir units have metal housing, not plastic ones, and are designed with powder-coated paint, preventing any off gassing. Their carbon filters are also lined with two additional pre-filters, providing increased filtration, and extending the performance of the HEPA filter. The carbon canisters are also refillable, making AllerAir units some of the most environmentally friendly and cost effective units on the market.