Watts and lumens just don't tell the story of how well a grow light will perform.
PAR (photosynthetic active radiation) is the best measurement of how well a grow light will perform. Happy Leaf LED lights are tested with a li-cor quantum meter to determine the par reading. Both the V1 and V2 of lights read at over 200 micromoles per square meter per second at 12" from the light source. The Happy Leaf V2 optimized grow rail provides 470 micromoles per second per square meter at 6" below the light.
The wave lengths of Happy Leaf LED lights are optimized at 450 blue and 660 red nanometers, the ideal wavelengths for chlorophyl A and B absorption.
If you would like to understand the full specification and use of LED grow lights, we highly recommend the following reading:
"The LED Grow Book: Better. Easier. Less Watts."
Christopher H. Sloper
"Commercial Greenhouse Production, Measuring Daily Light Integral in a Greenhouse"
Ariana P. Torres, Robert G. Lopez "Department of Horticulture and Landscape Architecture" Purdue University