Osram’s VIALOX NAV‑T SUPER 4Y 400 W is a high‑pressure sodium (HPS) discharge lamp for open or enclosed luminaires. On conventional control gear it draws about 415.5 W and outputs approximately 56,500 lm at a warm 2000 K with low CRI. The clear T46 bulb with E40 base measures 285 mm long by 47 mm in diameter. LEDVANCE specifies robust lumen maintenance and a median service life (B50) of 36,000 hours, with survival and maintenance factors documented through 16,000 hours. For indoor horticulture, retailers suggest using the 400 W NAV‑T SUPER 4Y over 80×80 to 100×100 cm areas, depending on reflector and setup. The lamp requires a compatible ignitor and is commonly paired with a 45 µF PFC capacitor when operated on magnetic ballasts.