When I became aware of the lesser quality seperators on the market I checked the ones I had to see if they were the good ones or not. I can't think of a way to verify the screen but I did verify that the inside tubes were the correct length by using a small piece if wire (coat hanger maybe) with just a slight bend or partial hook at the end. As I slid it down the tube I could feel where the tube ended then marked the wire. Holding the wire on the ouside of the can gave me confirmation that at least the tubes where the correct length.

Jim