These 2ft, 3ft, and 4ft Linear LED Kits were designed to retrofit existing troffers, wraps, and freezer applications. The ballast cover of the existing fixtures is used to quickly and effectively install each conversion kit. This retrofit offers magnetic installation (screw and tape options available), greatly reducing labor expenses. It utilizes our Patented Watt selector, eliminating the risk of purchasing and installing the incorrect retrofit power and light level LED conversion kit. It offers up to 130 lumens per watt. It is a cool running retrofit that will provide many years of maintenance free illumination in one of the most user-friendly packages available on the market today.