During any exercise, an individual's strength varies at different points. Other machines don't address this strength curve -- instead, the weight remains constant from beginning to end. This can limit muscle recruitment and overall performance. Enter Optimal Strength Curve Technology. Driven by our four-bar linkage system, cam design, or a combination of both, this unique technology dynamically matches the body's potential increases and decreases in strength. Users get immediate, smooth resistance and proper muscle loading through the complete range of motion. Uses the same 11-gauge steel from tubes and commercial-grade components as our other popular EVO® and XPLoad® strength lines. The Kevlar® reinforced belt drive system, double-sealed bearings, four-bar linkage and ultra-low friction guide rod bearings provide a longer life, a smoother feel and a stronger weight transport system than conventional cable drive systems. Marine-grade, contoured upholstery adds comfort, longevity and improved aesthetics over flat pads. Bright colored adjustment handles add to user-friendliness, along with fully-illustrated instructions on each station. Four key features: increased visibility through transparent weight towers; integrated 5 lb increment "drop down" add-on weight system; user-friendly molded accessory tray accommodates a variety of items; quick and easy seat adjustments with a safe and solid pop-pin system.