All the years I was in heating and cooling and all the homes I inspected, I have never seen this before. A 9 unit building with all new furnaces and all but one gas line going to furnace had this installed. Can anyone tell me what it is?
Picture is not the greatest. It’s black plastic with nothing going to it. You can slide it up and down the gas pipe and the two sides are held on by screws. It does have some weight to it.