there is no slot. The instructions are Push on base to unlatch and battery box will slide down. I pushed on the base and it moves slightly but not enough to push anything in to slide it down.
IT is a Digistat 1.
The battery box is a typical push to unlatch and push again to lock closed. But it will push not enough to unlatch. There is only the very slightest movement. I feat it must be jammed. I will have to buy a whole new unit, because the battery symbol is flashing and eventually the whole thing will die. Your reply seems to indicate a different model. You cannot help me I am afraid.