Excalibur Crossbow Rhino Nock - 

Excalibur Crossbow’s Rhino Nock was specifically designed to work in conjunction with models equipped with CeaseFire Anti-Dryfire Technology but can also be used on all Excalibur crossbows. The Rhino Nock maximizes durability and drastically reduces string wear.
Get Beacon lighted Rhino Nocks here: crossbowexpert...