FC BB 18W, FC DS 18W (Tesla Pančevo)

Here are the T8 tubes from Tesla. These tubes are both burned out DS one lost vacuum due to short circuit, BB one was used and got cathode broken. Color of DS on this one is about 5000K (factory used different coating for short period), BB color is similar to 33/640. Tubes have cathode guards, which was only seen on T8 tubes. Coating is as smooth as Philips ones.