On inserting the batteries in one of the units, ...
588525
On inserting the batteries in one of the units, the button that controls the grinder would not pop back up after releasing it.  It takes some messing with.  Will use it mindfully and hope that it doesn't become a problem.
2388596
This a a good product. It takes some finesse to get the batteries in and working, but once they work, they work
194827
Batteries may have been old. Shorter live than ones purchased @ local stores.
11553
Initial review is below.  After reading the review the seller contacted me and offered to make good via shipping a new unit or taking $5.00 off my credit card to compensate me for the new batteries I'd had to buy.  I elected the $5.00 as I had, indeed, already bought new rechargeable batteries and a charger.  I'm satisfied with their response to my uncomplimentary review but I stand firm that the manufacturer should be checking the batteries they send with their units to make sure they will work properly.

Right out of the box this thing is defective.  The batteries provided won't take a charge.  Rather than go through the hassle of sending it back I went to Harbor Freight and bought a set of rechargeable batteries and a charger.  I see others have had the same experience I have, i.e., the batteries supplied will not take a charge.  The manufacturer is not, apparently, paying any attention to the reviews.
4222126
Battery holder a bit funky! Great otherwise for a basic unit!
2259403
One arrived not working. If the led gets pushed in a little it stops working and you have to push the batteries down hard to push it back in place to make it work again.
825992
Bought two of the extra push button RPWL301A1006/A units from Amazon. The batteries that came with the units were very weak - close to dead. This necessitated buying two new batteries immediately - at an additional cost of about $ 3.50 each.  The units work flawlessly once a fresh battery is installed.

When you mount these, make sure you install the base so that the top side is properly oriented, otherwise the led on the button side will not be visible when you depress the button.
2094409
Received and one of the batteries will not charge.
1988144
While these units work well, they are designed terribly and replacing the batteries is a major hassle because you can't separate the casing from the mount easily.  Their larger units are easier to take off the mounting bracket and get to the batteries, but I can't recommend the small units mainly because of the design fault.
2529700
One hit & one Miss: One of the batteries did not fit properly in the camera.
One was just slightly larger.
2901095
One battery won't hold a charge completely. I want to make sure it is not the charger before
I get angry.
9736
I sent this as a gift to somebody, and just found out it was shipped with dead batteries. The recipient thought at first that the unit itself was bad. Thankfully  there's nothing wrong with the unit, but to ship something with bad batteries isn't good practice.
1454288
Plugging the connectors in is a problem.  It's not quality enough to keep the batteries plugged in to the charger.  With some patience, they all got plugged in or at least the lights are all on, indicating charging is happening.  We just received this so I'm not sure how the batteries will hold up over time.  I'll update if I learn anything meaningful.
1539497
The unit the company kindly sent me after the first unit failed to wrok is, so far working just fine. I drained and charged 3 sets of 4 batteries and no prob. I would now reccommend this product and, if the particular unit you receive has problems, to simply let the company know through amazon and they will replace the unit. well they did for me.
4954216
I bought 4 of these as replacements batteries for my Tripp Lite UPS I purchased from Costco over the past several years.  As other reviewers have noted (thanks for the heads-up!), some of these units clearly were not made for easy user replacement of the battery.  Two of mine were of this vintage.  Thanks to the warnings from other reviewers, I took note of the positioning of everything as I disassembled and they went back together pretty easily.  My other two units were, I guess, more recent purchases and the battery replacement couldn't have been more straightforward.  So far, the batteries are working just fine.  Time will tell...
3586073
One of the units did not 'unload' properly and is unusable.
3024715
The unit has two sliding plastic prongs which look like they need to line up with two of the contacts on the battery, and hold it in place just by the prongs. Not knowing which two contacts to use, I'm not about to try this until I can get the box translated. Even then I'm not sure if I will use it because it doesn't look like it will hold the battery firmly. Lithium batteries can explode when connected incorrectly.