This card works great with my Garmin Zumo GPS unit.  I mainly use it to hold vast numbers of songs, and it works great for that.  It is fast enough that my Nuvo has no difficulty accessing the memory and I note no slowdown in performance of the GPS.  Comes with an adaptor so you can use it in a regular SD card reader.  For my needs this one is perfect, hence the five star rating.  RJB.