ITEM NAME:F3 WHOOP PRO Mini Brushed Flight Controller FC Board for Micro RC FPV Drone Description: Built-in OSD interface Active buzzer interface (with buzzer) Comes with 6A * 4 brush motor drive, fully meet the demand Built-in voltage detection, alarm Flying control.BEC: Built-in 5V / 0.5A step-up circuit. Board weight: 2.5 grams. Board size: 28.5 x 28.5mm. People always bought together with. Active buzzer interface (with buzzer). Size Chart.