400w Poltava DNaT 400-4: Full Power

Nice old Soviet 400w SON-T lamp made by Poltava in the former Ukrainian SSR.
Interesting in that it has what appears to be a GE Lucalox style external amalgam reservoir.

The quality of the outer glass, like the other Soviet lamps I have seems pretty poor tbh, full of visible and tactile imperfections!
You can see the striations in the glass clearly here.