Oh yeah, about the warranty! This is important info. I think many folks believe the tube mfg is the one offering a long warranty and that’s not the case.
This is where the vendor really comes into play. The US tube manufacturers (L3 and Elbit) only warranty tubes for 2 years and modifying tube formats will void the factory warranty. So it’s on the vendor to warranty the tube if they modify it or offer a warranty beyond the manufacturer warranty.
Such as in our case, we warranty our TNVC built systems with a 10 year warranty on the tubes and lifetime on the rest of the system (housing, optics). We also warranty the L3Harris BNVD (PVS-31A), BNVD-1531, and M914 for 10 years whereas the factory L3H warranty is only 1 year for these systems.
Really, for the customer who is going to buy a modified tube and/or wants a long warranty, they should consider the probability of the vendor being around long enough and capable of covering their warranty. Tubes are obviously the most expensive component so a tube failure can really hurt if you have to come out of pocket to replace.