Well first off they add about 30 grains to the weight of the arrow. I bought one just to mess around with and it shot ok but it would only stay on during flight. As soon as it would hit the target it would turn off. Come to find out the contacts are too short and only connect during the shot when a lot of pressure is on them. There is nothing I can do to fix it, I'm just out 8 bucks. Not worht the cash imo.
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