The Folding Gravity Strider GS1 from V-fit comes with patented EZ adjust tension control resistance system with roller bearing thrust washers & four EZ adjust tension resistance adjustment control knobs. Dual independent striding action. Fixed frame support, ridged main frame end caps. Angled frame support leg end caps. Safety rails comprises of 30mm round tubular Steel combined with dual action & fixed safety handles with high density foam padded grips.