These fit in the Sipik sk98 and Aleto 26650 jumbo sipik (with 18650 sleeve)
Fasttech has BBC them but now the Keeppower 3.6 volt 3400 mAH are now the top dawg from hat I have been told.
Keeppower will be more expensive though, yes?
I have put in a request a few days ago for FastTech to start carrying the keeppowers 3400mAh, they told me this morning “we will update you when it’s here”
_
Others on here may wish to do the same, the more requests maybe the better chance they actually will carry them soon, but it does sound like from their reply they will carry them. I gave them a link to a competitor for the product that shows the price and graphs showing how good the batteries actually are.
I think FT will gives us a better price and a much quicker turn-around time for USA customers.
About 5-7.00 USD
How much better are the Keeppowers?
The battery inside is, of course, the same. The Keeppower protection circuit has slightly less voltage drop and considerable higher current limit (If this is good or bad can be discussed).
The Keeppower is 1 to 1.5 mm shorter, this can be very significant!
Thanks for the review.
http://www.fasttech.com/products/1420/10001980/1141104
http://www.fasttech.com/products/1420/10001980/1341105
Anybody knows the difference between these two types, beside one is cheaper? Which should I buy?
1st option is protected.
If you have to ask, it’s the one you should buy.
With or without protection.
Look at the pictures and read the description/listing guys 
They are BOTH protected
I looked at the heading, it does only say protected for one of them.
But you are right, both batteries has photos that shows a strip and a black extension at the bottom.
Except the photo with batteries in a box, there they do not have the black extension.
it has been discussed in the respective product page and haven’t got a response from FT. there is customer opens a ticket about it…
That is obvious a mistake, that a couple of sites made when the battery was new.
i received 4 cells from Wallbuys group buy (148 pairs or orders fulfilled!!) with nice iphone silicone XXX cases:
anyway, here are the measurements:
They fit well in all of my EagleTac lights (SX25L3, TX25C2, T20C2, D25LC2, D25A) but not in my Nitcore TM15 **ck. In € currency i paid a total of 20.76€ for these 4 cells altogether. ~5€ per cell. hmm. still too expensive? :D
Just a word of warning with these. they are long and I have found in a couple of my lights if I tighten the tail cap too much it dents the bottom of these cells. See image:
Will these fit an Olight M20?
The protected versions fit my M20 Warrior Premium R2.