pressure gauge. The old one looked clean and new but obviously had some issues as taping it with a finger resulted in the needle jumping one or two psi's. The Gas tech does't even think there was a real leak primarily because I smelled nothing and with the new gauge the pressure reads 20 psi more and hold steady with the gas valve closed at the tank. So its a "better safe than sorry" story because i could have swapped out the gauge myself but just did not want to risk it on something so potentially deadly. Although not truly analogous my next door neighbors, a guest and grandchild died of CO poisoning because of a faulty gas heater a couple of years back. What a tragedy. Thank you all for your advise.