Sorry to necrobump this old fellow, but seems there is a lot of speculation.
Been having these units now for multiple years, so about time, I put in my view..
It was what I needed hence my limited need & purse.. aka very cheap LPM for measuring my portfolio of NUBMs..05.06.07.08..
Lazing pictures
I purchased from this Laser Pointer Store 3 times.( all purchases are a couple of years back)
and my experience is 10/10 very very positive and all the items I purchased from Laser Pointer Store' I simply could not find cheaper anywhere else... Taobao, Aliexpress, or eBay. (doesn't mean that there prices in general' are the lowest, certainly not on some other items i saw there, and like everything here in life you need to perform your own due diligence)
I purchased
2x 360 glass mirrors, intended for lasers with a thick glass front. (8USD each)
1X Cyan Stubby 488nm (50USD) with a surprisingly decent 18350 included. (70mW)
2x LPMs (35USD each) (one with a battery and one without)
and the above prices became a tad lower after the use of coupons and cashback.
The packaging was great, for the 360 mirrors, the parcel-labeling gave no problems in danish custom, where prices often get elevated with another +35 to 50% after custom handling fee and another +25% VAT if the label is above 10euro, and they all were with free shipping.(perfect)
I thought the two LPMs were identical, and one just housed a battery and the other did not, but doesn't look to be the case judging by the responsiveness, where the smaller unit acts faster.
I get very consistent readings with both of them in the blueish spectrum, the smaller unit, is like 0.2% to 0.5% higher than the other
here is a run with a NUMB0.. it takes around 25s to 30s for a peak at around 6.300mW
battery
nonbattery 0.4% difference
Here is a brief look down at the smaller unit... looks like the sensor head is resting on a big chunk of aluminum.
I also tried when I got them back in hmm 2018 as I recall, to check how the sensor dissipated the heat with a thermal video camera.. (do recall I got some footage of it, somewhere)... and it was very even.
If I get the time.. I would try to make a review, with multiple diodes..
I tried yesterday with a NUGM3 with the LPM (small unit) a tad over 1 meter away.. it peeked around 1W but it still had the ball lens on that created a very tight line-beamspot so I didn't wanna floor it, as it is a 35USD LPM and the threes don't grow into the sky at these prices, hense the used sensor coating it, so I try to take my precautions, but over the years really have been impressed by these two units And if i should mess it up and destroy them, (like if I fx tried to tap into them for fx some data logging feed).. and I fried them.. I would gladly purchase them again.
IN regards to an aspect of reference, one of my friends has an Ophir head and DMM, and we used those numerous years back to adjust the driver pods of some of my DIY builds to certain absolute values, and in regards to those values, these two is surprisingly accurate... though it is 1W blue and some blue and green laser pointer that is down around 100 to 200mW. .. so not sure how well they perform in the higher ballparks in those wavelengths but in the blue.. they seems very good as long as you have the price in mind and a fully self-contained unit.
https://i.imgur.com/FRWH1bd.jpg
https://i.imgur.com/6Df7hxL.jpg