Our Model RX Destroys H2S odors from manholes. Stainless steel insert. Non-hazardous media. 18 gauge wall. Long-term life. Low maintenance. Our media is a hydrated iron compound which is mixed with wood chips and shavings and is supplied for use with our inserts for H2S removal. OdorKnocker Media is made from Recycled Material and may itself be recycled a second time! Our insert is pressed 304 SS from single sheet—no welds or patches. Our units will not break and fall into the manhole base due to traffic vibrations