GrowSun 20W LED Grow Tube
PAR stands for Photosynthetically Available Radiation. The PAR range extends from 400nm-700nm on any PAR measuring device, which is called a Quantum Light Meter. The PAR unit of measurement is called a micro mole, which expresses the photon flux density of light per square meter. The more micro moles you have per square meter, the higher your flux density is. The higher your density is, the faster your plants can grow.