Instruct: Classify Amazon reviews into positive or negative sentiment
Query: not working with Vista HCx

As other reviews have mentioned, it doesn't fit units with removable MMC card in the battery compartment, the instruction does mention that the original back cover has to be used, and needed to be screwed to the base of the mount structure. Well I did find out the screw, but it doesn't fit to the screw hole of my GPS unit. I had to get to a hardware store to find out the matching screw.I'm surprise there weren't a lot of people complaining about this design defect. Just a warning that if you have a MMC capable units, better double check.