Twin Pack LED Grow Lights for Indoor Plants: 12, 18 or 24 Watt. Seedlings, Vegetative, Flowering, Vegetables, Indoor Growing. Replaces CFL, Fluorescent Bulbs. Heavy Duty / 50,000 hours (18 Watt). IDEAL FOR ALL PHASES OF PLANT GROWTH: Works well with any indoor plant type set-up. Can be used in Green Houses, Grow Rooms, Hydroponic or Soil Based Set Ups. Flower Exhibitions, Cupboards, Bonsai, Sowing, Breeding and Farm based growing where you are trying to get maximum growth cycle over a shorter period of time. You get either 2 x 12W, 2 x 18W or 2 x 24W bulbs at purchase. OPTIMAL LIGHT SPECTRUM: Plants photosynthesis best using red light for flowering and blue light for growing. Your twin pack globes come with an ideal ratio of Red to Blue LEDs to cover the spectrum required. (12W/360 lumens= 9 Red and 3 Blue LEDs. 18W & 24W/540 & 680 lumens=12 Red and 6 Blue LEDs) (Red LED Wavelength= 660nm and Blue LED Wavelength= 460nm) (Each LED is 1 Watt). EASY INSTALLATION: No Ballast is required to power these bulbs. Just screw them into any E26/E27 fitting and they run off standard house current AC85-265V. Even a small desk lamp will power them. Use them as they are, or optimally with the aid of a reflective umbrella. Recommendation is to use 1 bulb per 30 sq in area at 30 in stand-off. Exact distance will vary with application. ENVIRONMENTALLY FRIENDLY: Being ultraviolet and infrared light spectrum free these bulbs are friendly to the environment. LED lights have extremely low power consumption and generate next to no heat compared to all other light types allowing you to have them on indefinitely. Working temperature is a constant 143F. YOUR GREAT WARRANTY: We are committed to providing you the very best customer service on Amazon, which is why our lights come with a 2 Year No Questions Asked Replacement Guarantee. Expected lifespan of your Grow Bulbs is 50,000 hours.