Gardens seem to have their own unique brand of stink. Some people come to like the smell, others can't handle it. The real problem is that those stinks often mean that you have harmful molds and other microscopic critters that are going to do damage to your garden. The 8" by 32" Standard Carbon Filter (Virgin-Activated Coal-Based Carbon) by DL Wholesale purifies 99.5 percent of indoor garden air and has an average life span of 1.5 years. An 8" flange is pre-installed and a pre-filter is included with your purchase.