These cells are courtesy of dcpower.eu, and feature an unusual chemistry - nickel-zinc. In fact, they don't compare to NiMH particularly well, developing a much higher working voltage, as it can be seen from the charts. A comparison between the different chemistries:
|Chemistry||Ustart (per cell), V||Ustart (4-pack), V||Uavg (per cell), V||Uavg (4-pack), V|
As it can be seen, the average voltage of Ni-Zn's is higher than what a fresh non-rechargeable cell develops. If the device is sensitive to input voltage, then it will behave as if it is on a pack of brand-new alkalines, all the time, provided that it doesn't smoke out in the beginning. Internet suggests that you don't use this chemistry in a flashlights with bulbs: they aren't calculated for this voltage and die when turned on.
Besides that, the other characteristics of these cells aren't particularly impressive: reports on the Internet suggest that they degrade pretty fast with each cycle; they require a specific, non-compatible charger; and their energy density isn't impressive despite the high voltage: they clock around the average for Ni-MHs, 2.3 Wh.