HKJ tested these…if you go to his comparator and look at the 50E vs the 50G you can see quite a positive difference.
They are also 2 years old, been sitting in a warehouse somewhere, then had magnets attached.
Neither of those matter at all, though. If they sat that long and were at nominal voltage then all should be well as long as it wasn’t extra high heat, or rust from high humidity which would be a good indicator of very poor storage conditions in typical unconditioned warehouses. Otherwise, charge ’em up, maybe let ’em sit to observe voltage stability, and know that it’s a better cell than the 50E. Still didn’t get what you specified and ordered, I know…
The magnets don’t ultimately matter but something is going on here.
They sent the wrong batteries after months of having no stock and what they sent is years old assuming its legit.
The magnets keep the electrons stuck together so they don’t leak out all over the package.
It’s high tech protection - fast tech, even. 
Well played!
Bort, I’m deeply sorry for the mistake and the inconvenience caused to you. And I feel terrible about causing you such an unpleasant experience because it was ultimately my responsibility.
When I promised you that the stock would be available after Chinese New Year, I didn’t realize that the supplier would fail to fulfill the promise. But it turned out they couldn’t give the stock when the time was nearly up. You’ve been expecting these batteries for so long, I didn’t want to disappoint you with the back and forth stock date again, so I decided to look for other resources from Alibaba. Then I found another resource with 6 years of store authentication that supplies these 3rd ones. Therefore, after double-checking the authenticity of the stock, I asked our purchasing team to get the stock from this supplier. But I never thought this led to an even worse result in supplying incorrect stock.
Generally, each of our products goes through several quality check procedures before the final delivery to the customer. It seems this battery might have slipped through due to the large number backlog of orders after the holiday. I’m sorry for not taking care of this because I should have also reminded them to pay more attention to the new stock and check them in person.
We regret we are unable to offer you a replacement right now because both the original supplier and this new Alibaba supplier confirmed that the 3rd generation of the 50E one is no longer available in the market. And it might last for a very long time. In this case, I’m sorry to say that it seems we have no choice but to issue you a full refund for your order.
I am grateful that you have brought this to my attention. It helped us avoid any future losses and inconvenience to other customers. This mistake caused a certain loss to our company. I’m taking full responsibility for this by coving the losses with my salary. I will learn from this and take any necessary steps to prevent it from happening again in the future.
Thank you for being a valued and supportive customer of our company for years. I would like again to apologize for the hassle you have to go through.
If you have any further questions regarding this order, please do not hesitate to let me know. Thank you.
Jasmine
After some PMs back and forth Fasttech and Bort have come up with a solution, summarized below (posted with the agreement of Fasttech as i would normally not make PMs public):
As mentioned in the post above they are unable to source 3rd generation cells. They offered me a refund but i asked about second generation cells instead. They said they can get these, then i asked how they confirm authenticity. They said they test them internally and are buying them from a supplier that they have worked with for a decade.
Below is the image of the test they did (they say knockoffs usually don’t have the same discharge characteristics compared to genuine)
Samsumg INR21700-50E 21700 battery:
Now i don’t know how this test compares to an authentic cell but i will assume its accurate.
Fastech, anty further info on this product? Cell quality, tested capacity, reputable manufacturer?
https://m.fasttech.com/products/1420/10018682/3867102-12v-4800mah-rechargeable-li-polymer-battery
aoeu, sorry to say that we don’t have the equipment to test this product. But after confirming with the supplier, the actual capacity of this battery is only 1800-2000mAh which is substandard. We’ve updated the product description and will pay more attention to this to avoid the same problem happening again.
We apologize for the inaccurate description and thank you for the heads-up.
Unfortunately FastTech was shut down in 2022: