A Tripmaster is a essential tool for Oldtimer & Youngtimer Rallyes or orientation trips to know the driven distance in comparison to the ROADBOOK.Functions+ Auto-Start+ Distance total+ Distance trip+ Counting distance total + / -+ Counting distance trip + / -+ Switching Counting up / down+ Manuel Change of distances + Reset total or/and trip distance+ Classical Retro LookNEW: External Remote Control reset trip - reset total Level your control experience with the external control of the App-functions with the Apple Earphones Control or hama Bluetooth-Control (In-App-Purchase). Much Success with your next rallyes...GPS: Continued use of GPS running in the background can dramatically decrease battery life