These automatic room temp-erature control valves balance low-pressure steam or hot-water systems and control the room temperature within ±1°F, says the manufacturer. The valves have a “memory disc,” which makes resetting a temperature position easy, the company says. The patented Easy-Demo tool permits exchange of valve inserts without stopping or draining the heating system. Valve sizes are 1¼2-, 3¼4-, 1-, or 11¼4-in., and valve patterns are straight, angle, or horizontal angle to match the heating system design.