I bought a pair of 6x prismatic loupes last year and within 6 months both ocular pieces came loose, and one fell out while I was working on a patient! The battery it came with also started malfunctioning and the light flickers on an off. They won't send a replacement battery for you to hold you over until your battery is diagnosed and repaired. And good luck getting anything back in a decent amount of time! I sent my loupes back over a month ago and I they still haven't been fixed. You have to send multiple emails to get a reply as well. I still have my original loupes from dental school that I am using as a replacement for now, and in over 15 years they have never had an issue. Buy at your own risk.