Well I can tell you they will NOT be on the arrows in my quiver this fall !
Problem # 1 does not say ( on the package ) what arrow it fits , nothing notta , just that is a flat back crossbow nock . ( did not fit 2216 aluminum id of shaft was to big , Beman Thunder bolt worked but snug )
Problem # 2 easy off switch . Just use the tip of your knife . Well I call BS . I ruined 1 trying to turn it off . Tried my knife . O - ring pick , ball point pen , etc .(
Check the website to see if there are better instruction than the package ---- of course, what do I find ....new website coming soon .

http://www.nockturnal.com/
I then tried the email address for the company , what else . That does not work either


My advice would be to stay with what I know works ----- Firenock , or Luminock .
These Nockturnals are going to the trash .
Will be adding this same post to crossbow section at AT