HM RB-S 120 is Harvest Master’s fanless Red Boost Silent variant for compact indoor grows. This 120 W LED fixture uses full-spectrum Edison diodes supplemented with 660 nm deep red and a passive-cooling housing, paired with Mean Well drivers. In a 60×60 cm test area it delivers about 840 μmol/m²/s PPFD at 50 cm and 655 μmol/m²/s at 70 cm, with listed efficacy of 2.17 μmol/J. The unit measures roughly 31×31×11.5 cm, weighs about 8 kg, and has a rated lifetime of 50,000 hours. Input is 220–240 V, 50–60 Hz. Harvest Master backs the Silent series with a 3‑year warranty. Recommended hang heights are approximately 90 cm (seedling), 70 cm (veg), and 50 cm (flower).
