This is the original (not re-branded) Gen5 Z-Wave stick with the newest firmware for $25
The actual product that you get will say ACC-UZB2-U for U.S. DigiKey just has bad picture. I have purchased and confirmed with Sigma Designs and DigiKey specialists via telephone that this is in fact a Z-Wave Plus with the newest chip.
As far as a Z Stick with battery. Who would use that? Batteries degrade over time. After a certain period, the Z Stick just has a dead battery with no possibility of replacement.
Some people question the necessity of the battery. This is home automation, devices are not added daily. I personally do not like a built in battery because you don't use it. Maybe once awhile.
This is the lowest price for a Z-Wave Plus USB Controller out there right now. Pair this Z Stick with Domoticz. The most affordable and best solution for home automation!
: This is a regular everyday low price. I had purchased RazBerry ($70), Aeon Labs Z-Wave Plus Stick ($45), Z-Wave.Me USB Stick ($35) before I found out of it existence; too expensive and one all plastic even the USB plug. Sigma Designs UZB2 Stick works the same and it has newer firmware. I have replaced everything with Sigma Designs UZB2 Stick now.