I use Beemans.
Lighted knocks are the ticket. In low light situations, you can see exactly where you're shooting. Bad azz. They're a must have.
I started with Luminox, but it turns on when the string pushes on the knock. To turn it off, you wiggle it out a little bit. The problem I have is that the knock can turn on accidentally and run down the battery.
So I switched to Tracers. They are activated by passing by a small magnet that you stick to the riser. The light turns on solid and after a few seconds begins to blink. Not only can you see it fly, but then you can find your arrow. One time during day light, I shot a deer but couldn't find my arrow. So I went back about 4 hrs. later in the dark and low and behold there was my arrow stuck in the dirt with the Tracer still flashing. To turn it off, you simply hold the knock next to the magnet and it turns off. They're a little expensive, but they're worth it for the hunting experience of being able to see the flight of the arrow.
