I have the TPI775 in addition to a Tiff 8800 and Tiff 8800A. I have not had any problems with the TPI, but have found that I don't use it as much as I thought I would. The flamable gas detection head is much bigger than the Tiff and therefore remains farther away from the pipe/fittings, but it does work. Plus, the CO detector is built into the back of the body, not on the wand as one would think. If I had it to do over, I probably would have bought the Bacarach (??spelling??)and added it to the Tiff. I guess that if I didn't have the Tiff, I would use the TPI exclusively. One caution, since it has a push button power switch, it does hav a tendancy of turning itself on. Always carry extra batteries.