These have got to be the biggest pieces of crap I’ve wasted money on. I went with the 7watt. It worked well four about an hour of run time then the button that switches it on and off got stuck and before that the laser was getting stuck on low power a lot. The base where you screw in the batteries started getting touchy to where it had to be screwed in a certain amount of length or it wouldn’t work. Sanwu’s customer service has been horrible at best. They tell me to fix the base switch myself which looks to be mad impenetrable. They’ve basically told me to piss off throughout this ordeal so let me suggest to stay the heck away from Sanwu.