Med-Fit Systems 2009 Core Upper Body Lower Body View Available  Colors Use the color change demo to create a custom color combination for your equipment.   Download a Custom Color Chart (Please note: Standard frame color choices for Nautilus Commercial Free Weights include only Silver or White. Black and Powerhouse Granite would require custom color treatment and lead times.) 1.800.831.7665 1.800.831.7665 Nitro Barriers: Zero. Performance: Amazing. 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. Nautilus Nitro® equipment users get immediate, smooth resistance and proper muscle loading through the complete range of motion for better, quicker results. For a powerful workout that is intuitive enough for novices, select from the drop down below to view the Nautilus® Nitro line of equipment. Nautilus Nitro®