well I used one for a few yrs before going to an X bow
there are several models out there, some better than others, and I even know a few guys that rigged up there own to come on at full draw, and off when not and some that did pressure switches on the grip, so again only when drawing and holding draw would they come on!, actually had that set up back in the late 80's early 90's, by a local bow shop, custom sights he sold and made!, worked great till them broke LOl but got 10+ yrs out of them! then fiber optic's came out and tried for yrs without the light!
you can try putting some bow string wax on the treads to keep it from walking off too, or likes
one thing I did notice about them is if there too bright they shadow out the target, so lower , less bright was always better
and LED , batteries last a lot longer