See plant and turf stress 2 to 10 days before it is visible to the naked eye! Utilizing technology developed by NASA scientists, the premium quality polycarbonate lens blocks out the green spectrum reflected from chlorophyll found in healthy vegetation by making it appear black or gray. Plants and turf impacted by drought, disease, or poor nutrition appear as glowing red, coral, or pink. The polycarbonate frame provides a comfortable wraparound fit, and the quick change snap-in lens system allows you to exchange the plant stress detection lens for the included flame copper sun protection lens (400 nanometer UV A-B-C). Soft case and micro-fiber cleaning cloth included.