bought this rangefinder 15 months ago and have enjoyed it for two seasons, but last week it stopped working. So far it has worked very well. The flag finder feature was particularly impressive. So far I have been 100% satisfied with the item. When it stopped working, the symptom was that I couldn't see any lines, crosses, or numbers in the viewfinder. The power was completely gone, although the device was fully charged before leaving home for a golf course. When I asked for help, the seller asked a few questions about the symptoms and kindly offered a 50% discount coupon even though the one-year warranty had expired. After buying the second one at half price, I wanted to disassemble the non-working one to see the inside. Long story short: I found a way to fix the problem. The culprit is the rubber cover over the power button. The rubber cover was easily removed by simply pulling up with a slight twist. Its interior was worn out, pinched by the edge of the case and pushing down the power button — meaning it was losing power all the time. So I put a small piece of tape on the worn part of the rubber cover inside. This prevented the cover from being pinched by the plastic casing around the power button, and voila, the rangefinder worked again! I see several reviewers complaining about a sudden power outage and my advice on this is to see if the power button works with a clicking sound. If there is no clicking sound (even if the button goes down), open the rubber cover and do something to release the power button. This item serves its purpose well and is very inexpensive.