Illuminated Firebolt Arrows are designed specifically for your Excalibur crossbow to ensure the best possible accuracy while using both fixed and mechanical broadheads. These Firebolt carbon arrows come equipped with Burt Coyote's (.3015 dia. EXCF) Lumenok illuminated insert that have been professionally installed. The Lumenok is activated by the accelerative force placed on it when shot from a crossbow. The lighted insert aids the shooter by providing an illuminated path to the target and will assist in arrow location.