The 400W sodium vapor lamp is the shining classic among lamps. Professionals like them because of their reliability and good price-performance ratio. The light spectrum of the HPS 400W from Caluma is aimed at the flowering phase of plants. But it also delivers good results in short growth phases. For connoisseurs, we would like to point out that the photosynthetic photon flow (PPF) of the lamp reaches an unbeatable 733.2 μmol. / Second.