BAS is the upgraded model of Frisbee that also is powered by built-in lithium battery. The 2600-mah battery enables 60-minute cleaning for the pool bottom. The brand-new “Touch & Reverse” Technology: Touch wall and reverse running direction. No need to rotate the turret to achieve direction reverse like basic Frisbee. Frisbee Pro performs better and has a more stable direction reverse than Frisbee. BAS can automatically move to the pool edge when the battery runs out.