Sylvania 350w SHX Mercury Retrofit

1 x 350w Sylvania elliptical coated high-pressure sodium lamp designed to replace 1 x 400w high-pressure mercury vapour lamp on the existing control gear.
These lamps offer increased lumen output and reduced energy consumption compared with a 400w mercury-fluorescent lamp.

Unlike a Philips example that I recently acquired, this lamp measures almost bang on the rated specifications.