Bullfrog A Series Spas and R Series hot tubs by Bullfrog Spas feature the patented JetPak Therapy System™, the only spa design that allows you to select the specific massage experiences you like and place them in the spa seats that work best for you. Additionally, you can interchange JetPaks at any time and update them as your needs or preferences change. You are empowered to completely personalize your spa, leading to an ideal spa experience and a more peaceful life.