I used the B & L 10 power lighted magnifier for 15 years while an inspector of printed circuit bosrd assembly. It was indispensable for me, I was never without it. The threaded end wore out and I had to hot melt glue it on until the battiers or the bulb gave out then reglue the magnifier back on to the cylinder. The bulbs do burn out quickly unless you can get good quality ones. If you can inspect the bulb before you buy it check that the filament is intact. I went through three units in 15 years - using everyday.
This review was written in the old system and had content requirements that are different than reviews written today.