I recently purchased a BGN 35mm wide angle for my M645 Pro, and it's absolutely perfect. No problems, performs excellent. Only like $69! What a deal! I've been buying from them for 10 years or more. Never any problems. If you're so worried about any little thing, then don't buy it. Simple as that. Even if you get it, you WILL find some teeny tiny fault with it, and be pissed off @ KEH for selling BGN grade stuff. So, just don't do it. Save up for a better grade, and be done with it.