The Accuracy 1st DG, Inc. anti-cant scope level light slides and locks onto the Accuracy 1st scope level. Made exclusively for Accuracy 1st, our light has (3) light levels for varying degrees of brightness. Our battery powered scope level light has approximately 1,000 hours of life on the lowest setting. An automatic shut off option kicks in after an hour of use to prevent draining the battery in case being accidentally left on. Once the battery life has ended, simple remove and dispose of the scope level light and purchase a replacement.