According to vehicle code 24411 anyone with any auxiliary lights being operated on any highway your lights are to be covered. These covers will make your LED lights street legal. (requires install of small magnets on the lens of your light) Has no affect on the light, output, or warranty. Covers include everything for the installation (Magnets and Glue)
Cover sizes are referring to the length of the lens. For example a 32" LED Bar Has a lens length of 30".