The first of its kind, this is the self-propelled luggage that automatically provides power assistance when you encounter inclines or are straining to roll the luggage. Sensors in the handle monitor how much force you are using to pull the suitcase and signal to electric motors in the wheels to engage when you are struggling, propelling the suitcase up to 3 MPH. The power assistance initiates only when the suitcase is in motion, the handle is pulled out from the suitcase, and it is tilted between 15° and 35°. When you encounter declines, the motors disengage, allowing you to control the unit like traditional rolling luggage. The handle and suitcase are designed so that 85% of the carried weight is transferred to the wheels, reducing your load and enhancing maneuverability as you navigate terminals. The suitcase is made from injection molded ABS/polycarbonate composite--the same material used in automobile bumpers--that provides superior impact protection, and both halves are conjoined with steel hinges that are riveted to the case. There must be at least 15-lbs. in the suitcase for the power assistance to operate; holds up to 70 1/2 lbs. The integrated battery lasts up to 2 1/4 hours (or 1 3/4 miles) after a full charge and recharges via AC (adapter included) in five hours. 32 1/4" H x 19 2/3" W x 13 1/2" D. (23 lbs.)