Used these to rebuild and upgrade the battery pack on my Porter Gable drill. Original pack was full or 1500mah batteries. These almost doubled the run time on the drill and the circular saw I use. Building your own packs is a labor of love, but the results are perfect.
I have not had them long enough to comment on longevity.

Batteries all arrived at 1.2 volts. After installing them, put battery pack on a 2 hour charge and to date the batteries are still holding a charge without using them. Have not had the need to use my drill but will update my review if any issues occur.

I got a few of these 8 packs to rebuild some old DeWalt 14.4v power tool batteries. There's only 12 cells in the 14.4v battery packs so I didn't want to pay for the 15 packs that are more common for the 18v batteries and end up with extra cells I won't use. I also like how these are paper wrapped for heat insulation like the original cells are. These cells are the exact same size as what's in the DeWalt packs. Cost me about $28 per 14.4v pack, which is about the same price a new, knock-off brand battery. Except, now I know I've got quality cells in my battery packs that will last and they actually have the claimed amp hour life...who knows what's actually in those knock-off brand packs?

Swap out was easy, just make sure to map out how the original cells are "wired" together and how polarities are oriented. Place the new cells in the bottom half of the battery case to hold them, solder the tabs, flip all the cells in the case and repeat, done.
The tabs on these cells are long and thin, which was great for orienting them correctly to reach whatever adjacent cell they needed to attach to. I could bend them over to the opposite direction, or at a different angle without any loss of clearance and without having to pop them off the cell and re-solder back on like some people said they had to do.
There is heat shrink on the tabs for shipping, as seen in the pictures, to prevent them shorting out on each other. The amount of questions and statements on here from people not knowing what the heat shrink is or what to do with it is kind of concerning...if you don't know what that stuff is or what to do with it then you probably should not be rebuilding and soldering battery packs...

Used these to rebuild an old Craftsman drill battery from the 1990s that had totally worn out. They take a while to charge (might be the fault of the old charger -- it's just a 20v wall wart into resistors to drop the voltage, no regulator or even diode in place. will be rebuilding that) but these batteries seem to have solid longevity. Not as great as the batteries in other power tools I have with similar voltage / mAh ratings but it keeps my old drill really powerful and strong for several hours of use.

Replaced a 13 cell, 15.6V, hand held vacuum battery pack. Works great so far. Not yet sure how ong they will last, but so far so good. Inexpensive. Kind of wished I went with NiMH instead of NiCd.