Named after the iconic 633 water valve, the DEMA Blend Center is one of the most well-known chemical dispensers in the world, with decades of reliability in its legacy. The Blend Center’s modular design lets you easily couple together any number of stations to create any system to meet your needs. Mix and match 1gpm (4 liters / min.) and 4 gpm (15 liters / min.) and choose from blue, red, green, yellow, or white buttons. Models include either Action Gap or air gap backflow protection.