The Spirit River UV2 Strung Saddles are made with key colors infused with UVF and UVR. They usually run 5 to 6.5 inches. Spirit River&';s are some of the best in the industry and they have an extensive line of regular or ultraviolet UV enhanced saddles. These are strung and being from a rooster they have a stiffness and bounce. Spirit River continues to lead the way in UV2 technology. They have used a double dye process to give all their unique UV2 materials and flies the added UVF/UVR ultraviolet wavelengths. UV Fluorescence are so common on everything from street signs to bass lures. UV Reflectance is a spectrum of wavelengths humans can not perceive yet is extremely common in the animal and insect world. UVR allows mayflies to find mates, and bees to find flowers. Many male birds and bugs have a strong natural UVR signature.