We use tweezers to access the SD cards.  They are not meant to be accessed frequently so they are a bit harder to get to.  Also when you replace the SD card or powering on when not connected to WiFi you will want to make sure there is a blue LED light that flickers next to the SD card from time to time (the logging period). If it flickers three times, the SD card itself was not loaded properly and not logging data. It is helpful to have them connected to WiFi to make sure they are logging correctly, but realize this may not be available.  In order to get any future firmwares update you will need to be able to connect the sensor to a network as well.