Accurate under any light source. SpotOn Quantum PAR Meter Designed by Innoquest president and licensed engineer Bill Hughes, who has created over 75 agricultural and greenhouse products, 17 of which have won AE-50 awards from the American Society of Agricultural and Biological Engineers. Trust SpotOn to deliver accuracy SpotOn Stacks Up Well Against The Competition Our meter is trusted by researchers and scientists for PPFD measurements under all types of lighting. From LED to sunlight the SpotOn is an excellent choice. Easy to use and read with a .75" LCD display Bill Hewes, Inventor of SpotOn Bill Hughes, inventor and President of Innoquest. Meters for the rest of us You don't have to break the bank to acquire a quality par meter; affordable models can be just as effective. Feature packed multi-tool Cleverly designed with an integrated stand that converts to a garden stake for stationary DLI readings. Pride of ownership The SpotOn is easy to hold and read with it's half inch high LCD screen. Daily Light Integral Built In Compare PAR levels to anywhere on earth Daily Light Integral is the amount of light that a plant gets in a 24 hour day. In nature, the amount of light varies all day long. DLI measures the total so you can compare it to anywhere on earth. Simply set the SpotOn down for 24 hours When you return DLI is displayed when the power button is pressed. Use this reading to match up to any environment on earth using a wide variety online DLI lookup tables.