Today, German discount chain LIDL is selling a 2.5x magnifying glass with LED lighting.
I bought one and I'm plesantly surprised. So here comes a mini-review:
At a price of EUR 5.99 I didn't expect too much, but I was so wrong. The body is nicley-machined aluminium (no HA, for sure). Batteries, a zippered case for storage and a cloth for cleaning the optics are included. There's a 5 year warranty on the product.
The light switch is a pushbutton that lights up 4 LEDs upon the first click and 8 LEDs upon the second click. The LEDs' brightness is just right to examine small objects clearly without glare. The light is smooth and lights up objects evenly from all angles. The tint is slighly on the blue side, a non-flashoholic doesn't notice it.
The LEDs run off 2 AA cells, using a very well regulated (!!) converter. The converter is actually amazing, something I would never have expected at this price and on such a product. It maintains constant light power b/w 1.4 and 4.0 V, making the very best use of the batteries.
If you like to dig deeper, here's the spreadsheet.
Without having disassembled the unit and based on my electrical measurements only, I assume that all LEDs are connected in parallel. There's however enough voltage drop that this circuit could operate off a fully-charged single Li-Ion cell (but careful, it will discharge an unprotected cell to an unacceptably low voltage).
Finally, a few photos:
Here's a scan of the manual:
Bottom line: This product will stay with me for a long time to come. The only thing that I feel could be improved is the weight. Some stamp collectors might consider it a bit too heavy for extended periods of usage.