I am glad to see someone else saved one of these special tubes. The colour may be the typical American dull grey, but its construction is rather special and was the US answer to the T8 krypton-filled energy saving tubes developed in the 1970s in Europe. That concept did not work in USA where most ballasts are rapid-start types, and provide insufficient voltage to strike a krypton T8. So their solution was to use an argon-krypton filled T12 which is somewhat easier to strike, but still not compatible with RS ballasts. A metal stripe as used in EU was also not sufficient. To further lower the striking voltage, Westinghouse coated the inside of the glass with an electrically conductive transparent film of fluorine-doped indium oxide - almost identical to the tin-doped indium oxide films of SOX lamps, which are also excellent electrical conductors. The tin was changed to fluorine because the former reacts with mercury. This film acts like an internal auxiliary electrode and enables these tubes to strike reliably on the low open circuit voltage available in USA.

Thanks for the info James, didn't know any of that, very interesting

Interesting!

This one of Best 34 watt tubes out there. these will last a long time. I have some sloppy seconds philips alto still going at mons basement that still going from 2007.

I'm not a fan of F34's, but I always did like the etch on these..