Easton tracer nocks turn on when passing over magnet...upon impact they switch to a blinking mode [to save batteries] and make it easier to find. i mounted the magnet with epoxy. i used these with great success!!
Also to shut them off ...just way them over magnet...to shutdown for the season just hold nock over magnet till you see a series of flashes..shut down is complete..i have some that are 5 years old.90 hour battery life....since i installed my first ones i have never lost a arrow. even when deer break your shaft... you still get your arrow back.
Same here, they seem pretty nice. My son shot a few doe with them in the late season. He said it cool to see them fly at the deer. it actually startled him on the first one, it was so bright. Kinda tough to turn off, till you get the hang of it though.
One of the reasons is that these nocks are composed of about 60 percent less nock material than Parker mag nocks. When a nock fails it basically causes your crossbow to dry fire. Nock failure is the most common reason for cracked limbs amongst other issues with crossbows. That is why parker is now only suggesting that parker mag nocks and parker bolts be used with Parker Crossbows. All of the 2010 models have stickers on the limb regarding this. Here is a link to Parker mag nock. Here is a link to the parker mag nock http://parkerbows.com/pb/2007/RHcrossbowacc.html?action=detail&detailsku=1081