Taco, Inc., now offers its Plumb n' Plug cartridge circulators with optional clock timers, including a new digital clock version that can be programmed for up to seven days. Taco's Plumb n' Plug cartridge circulators can save up to 25 gallons of household water per day. The analog clock timer can be programmed to activate the circulator during peak water usage periods, such as first thing in the morning or during evening hours. Taco, Inc. Circle 5.