Rocker Pinch Valves from Z-Man Corp., Grand Rapids, Mich., feature a brightly colored On/Off switch that pinches soft-wall tubing from 0 to 60 psi closed for extended periods of time. The rocker and combination rocker with a flow control valve come in 1⁄8, 1⁄4, and 3⁄8-in. OD tubing. Free sample valves are available.