* The Color Rendition Index (CRI) is a way scientists determine the light quality in terms of color accuracy based on the color temperature of the light source.  Generally speaking the higher the rating, the better the light 

** The Visual Comfort Probability is a scale devised to predict discomfort from glare

Since the Premium Gradient Filter improves the color temperature of a typical (cheap) cool white lamp from about 4200 Kelvin to about 6200 Kelvin, the CRI quotient moves from about 61 (poor) to about 92 (very good).  The filter allows certain critical wavelengths to pass through the filter that enhance the users ability to actually see better with less light.  This scotopic effect means that the physiology of the human eye discerns with less effort when working with certain parts of the spectrum under lower light conditions.  Specifically, lower overall light levels with spectral energies relatively higher in the region just above 500 nanometers means that the eyes work more efficiently and the overall result can mean lower energy costs.     The Filter utilizes end caps that create space between the lamp and the sleeve.  The polycarbonate sleeve is designed to stand up to heat generated by the fluorescent lamp for years of trouble free use.  Sleeves are designed to be reused when lamps are switched out.  The GRX380 Filter conditions spectral light output much closer to the color balance found in natural sunlight creating light that has vastly improved accuracy in color rendering.  In short this is one fantastic and inexpensive way to improve the quality of cheap cool white lamps while reducing the overall light levels in a work area.