SPRI Xertubes provide an easily portable, highly versatile way to add resistance training to your workout. Constructed of durable rubber with secure plastic and webbing handles, the Xertubes are suitable for a variety of toning exercises, body types, and fitness levels. Color-coded red, this Xertube is recommended by SPRI for the upper body workouts of most men and fit women. It offers medium resistance for the muscle groups in the back, arms, shoulders, and trunk. SPRI also includes a strap that lets you safely secure the tube to a door for additional target activities. The kit includes two illustrated charts of exercises, including bicep curls, shoulder presses, and back extensions. Designed for light and speedy mobility, the strap can be rolled up to stash in a gym bag, suitcase, or overnight grip. –Emily Bedard