I purchased a Nikon buckmasters 660 rangefinder about 18 months ago.I,m not sure what caused it to malfunction butit was never dropped or abused.After sending it back to nikon they informed me that it would be cheaper to replace than repair.They were sorry that it was no longer covered by warranty and offered to replace it at a discounted price.I requested a monarch 800 and they said it was on it's way.After six months and countless calls to nikon Canada in toronto I was becoming frustrated.After almost a year they finally ended up sending me a monarch 1200 which works ok but is physically much larger than an 800 and not really suited for bowhunting.I hope Nikon USA has better customer service than canada but I wouldn't hold my breath.I guess I have really learned my lesson.