Lumenok Easton Carbon Crescent Bolt End (3-Pack), Red ECC Easton Carbon Crescent - For Easton Carbon Bolts .297" on the ID The Lumenok is a Red lighted arrow nock used for shot placement recognition & arrow retrieval Now equipped with a easily replaceable battery Fits .297" ID shafts Red crescent end Easily replaceable battery 40 hours "on" time, 4 year shelf life