batteries last about an hour (with rechargables)but you can buy spare batteries on ebay for about £2.50 a pair.there was a problem with the bulbs blowing but i think it was just a bad batch coz the replacment i got has been ok.the original blew after a couple of outings and when i went back to the shop they said mine was the forth to go back but i got a free replacment.the beam in ideal conditions go ,s for about ish yards but on a 12ft lb gun you dont really shoot above 50 yards anyway.i tried it on a bruno 511 rimfire and it was a bit under powered.if you are thinking of buying one id pay