cordless combi drill driver electric battery power screwdriver with bits set 21v

2 speed transmission for screw driving and drilling: low speed(gear 1) for great torque, suitable for screwing big bits. high speed(gear 2) for small torque, appropriate for fast screwing. 18+1 position with clutch to prevent stripped screws: 18 gear of torque with clutch to protect screws; 1 gear of drill is deal for drilling.