This is a tube that I got when I was 11 years old. For some reason I just now got to it and made a presentation on it. It is one of the very first fluorescent tubes I ever got actually. I got it from (if I remember correctly) from the electrical store that was near my old place that I used to live in 4 years ago. I asked if they had any spare old lamps to give for me for free because I had a collection, and after many uncomfortable stares and akward silences They went to check and they brought two tubes, this one and one NOS 1995 Pila (Polish made Philips alternative) DL F40T12. This tube is used, but still has it's cathodes intact and has some moderate life hours left in it. It is Unusual F40T10 DL fluorescent tube, made by a soviet-and still existing lamp manufacturing company SVET (witch in English svet means light) amazingly it has a T10 sized Tungsram endcaps. I have a full collection of those :D I have a T12, T10 and T8 Tungrsram T12 encap alternatives. Being Russian made in 2007 this tube is moderately bright, but it has a defect. If you look at the whole tube pics, you will see that the tube is not as bright in the middle as near the cathodes. There is two pics - the upper one shows the tube, cold start after 4 years pf non-use and the botom one is after the tube running for 10 mins after photoshoot. You can see it doesn't want to get bright in the middle. And the arc is not wavy as you would expect - It is not mercury starvation! It is some different defect in the gas blend probably. I don't know. Maybe some of you can explain what the hell is going on here :)