A friend bought one not sure what brand but it was worthless. Even when we could see the blood trail it didn't do anything.
What it was good for is finding lost arrows in the dark if the have fluorescent knocks on them.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli