This device has several inconveniences, the codon is too short, the bag falls from its slide without stopping, starting is too hard, you have to press several times to start it, it hurts in the palm of the hand force support it, the cord does not have the automatic winder system to polish the stair treads on each step, we should stop waxy, forcing us to rely heavily on well-sleeve that causes pain on the palms of the hand .....