Feature: About 48 hours of battery life (non-replaceable). Bowstring Activated On-off Switch. Lightweight and precision-balanced for superior accuracy 0.204 nock with H, S, GT collar fits 0.233, 0.244 and 0.246 ID arrows. Specifications: Color: Green, Red, Blue, Flash Weight: 20 grain How to use: Nocks can be inserted to the shaft easily and in fully operational condition. If need to use the collar, assemble the collar first then the nock. Automatically lighted after shoot, there is no need to turn it on manually. Nocks can be turned on or off by Up switch. Package included:3pcs lighted 0.204 nocks, 3pcs of each size collars, total 9pcs collars