The Dirty Bird septic pipe cover uses a charcoal filter to fight odors. It is available in three colors and fits into the landscape disguised as a pedestal birdbath. It can used to conceal pipes from residential AIRVAC 4-inch vents. The three-step installation requires cutting a 4-inch vent at 22 inches above the ground and placing the unit over the vent pipe. A stainless steel screen is installed to accommodate the flow requirements of the AIRVAC system. 866/968-9668; www.thedirtybird.com.