Garmin Alpha T20 GPS Dog Tracking CollarGarmin Alpha T20 GPS Dog Tracking Collar. The Garmin Alpha T20 is the tracking only counterpart to the TT25, same range, same battery platform, same handheld compatibility, just GPS without the training functions. The right collar for dogs already trained or for adding pack members where stim and training are not needed. Same Wi Fi auto updates, USB C charging, and Alpha handheld compatibility as the TT25 at a lower price point. Key Features GPS