Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Works great

This stuff is very hard to find. It's not for patching holes in your muffler; it's for sealing slip-fit exhaust pipe joints and flanged/gasketed joints. The sealer doesn't get hard, but stays pliable, doing double-duty as an anti-seize agent so you can disassemble the pipes 15 years later. You do have to have a tight fit so it doesn't blow out. I would not assemble an exhaust system without it.