I wrote this for the electronics mob but it applies to the DIY vaping mob too.

Purchased from ebay: Dental Surgical Binocular Loupes Optical Glass 3 5X 320mm LED Head Light | eBay

Purchased for AU $$63.99 (though they now seem to be going for $69.99).
Postage: AU $6.50, took ten days to arrive including two weekends which was exceptionally fast (to suburban Tasmania).

Feedback for the seller is not 100% but after reading through a few negative and neutral comments I decided most of the complaints were either user error or expecting too much from cheap Chinese products and the seller did seem to want to resolve problems. I have no association with the seller.

The items arrived packed in a plain cardboard box with ~1cm HD foam padding and parts dividers. This was wrapped in a bubble-wrap plastic post satchel. Should survive all but the worst mail throwers.

There was no manual included.

Set up was quite easy though not without issues.

An Australian pinned switch mode power pack was included to charge the battery pack. I have not split the case to check the quality. The pins do face the body of the plug pack to the right hand side so it does interfere with other plugs on a powerboard unless in the far right socket.

The light will not operate while the battery pack is charging.

The LED is a cool white with a good bright spot perfectly sized to the image circle through the loupes and has a reasonable and linear brightness adjustment range using the pot and on/off switch on the battery pack.

The light clips over the nose piece reasonably securely with a friction fit. Not likely to fall off though a dab of superglue or epoxy would fix it in place permanently.

There is a shirt/pocket cord clip included but I did not use it. I cable tied the light power cord to the left arm of the glasses (ties not included).

The glasses do flex a bit but can carry the weight of the loupes and light easily. The nose piece pads are comfortable.

To set up the loupes I removed the lens dust caps and adjusted the interocular distance, toe in angle and vertical angle. I found I had to drag the left side of the glasses down to level the two loupe images horizontally. Closer inspection revealed the nose mount had not been drilled level on the glasses.

A slight slotting of the mounting holes in the loupe mount with a Dremmel fixed this problem.

I could then merge the two images easily into a stereoscopic image and align the light. Focussing on a ruler and blinking alternate eyes while trying to make the numbers in each image as close as possible to overlaying one another was the most effective way I found to align the loupes.

I have the friction of the adjustment joints set so that changes can be made if required and the loupes will maintain the setting unless handled roughly.

The image circle is about 4.5cm at the focal distance. You could get wider if you are able to merge widely separated images easily.

The lens surrounds do produce a noticeable border to the image circle but it is not distracting. It is easy to look past the loupes (above or below) to see the wider view.

There is a very good 6cm depth of field.

There is the expected spherical distortion and chromatic aberration associated with cheap glass lenses. This is not excessive though. The field of view remains sharp almost to the edge and you really have to look closely to notice any edge softness.

On the whole the image is clear and the really good depth of field makes focusing on small work areas like soldering or part inspection very easy. The light helps immensely.

There is reasonable light baffling but the lenses are not coated. I did not notice any internal reflections.

The focal distance of 320mm is perfect for me sitting at my bench - I'm 170cm [s]tall[/s] short. Normally I bend over the bench and get quite close to my work. Not good for my back. With these loupes on I am sitting straight and comfortable in my chair when focussing on my desktop

If you a a taller person they are available in 450mm focal distance too. The easiest way to check which model you should buy is to sit at your workbench and run a tape measure from the bridge of your nose to where you are going to work.

I replaced the neck strap with a spare I had laying around from a pair of sunglasses as the included strap does not fasten securely to the glasses arms (the rubber loops are a bit loose). When I use the glasses I cinch the strap up behind my head as a headband. This adds a bit of stability to the glasses but is not really needed.

On the whole I am very happy with this purchase.