Using a servo-control system to drive motor accurately.When you stand on the hoverboard,the power plant will move the wheels forwards or backwards to keep balance,allowing full 360 degree maneuverabilityUL 2272 Certified self-balancing scooter pass all UL safety regulationsmaking sure your hover board is 100% safe for you and your familySafety Warning: Overload may cause injuryWeight Limit: 44-225 lbs.(20-102kg)Climbing Limit: 16? depends on terrainSpeed Limit: About 6 miles/hr (9.6km/hr)*When the speed is getting close to the max allowable speed, alarm will ring.*User will be in balance within allowable speed; while if speed exceeds the specified speedhoverboard will tilt the rider and adjust the speed to stay in safe range.Range: 6-9 miles.(9-14 KM)Terrain:Smooth and flat surface will increase the riding distance.Weight: Weight of rider will riding distance, a light user will have further range than a heavier userAmbient Temperature: 0?C-25?C or 32?F-?FMaintenance: Resonable battery charging and maintenance will increase the distanceSpecification:Size: 584mm*186mm*178mmMax Speed:9.6km/hMax Load:102kgCharging Temperature: 10-40?CCapacity:4.0AhInput:100-240V,50/60 HzOutput:42V 2ACharging Time:2-3 Hours