The F854 is Cal Spas' first 8-foot fitness hot tub. Fitness-conscious spa-lovers can now perform several common exercise routines —including rows, curls, stretches and jogging—in the convenience and comfort of a Cal Spas hot tub. Most importantly, the F854 reduces chance of injury and muscle soreness by providing 54 spa jets to massage back and leg muscles before and after workouts for warm ups and cool downs.