A valve unit capable of being implanted in a patient and having adjustableperformance settings, suchas pressure settings and/or flow control, to regulate passage of a bodilyfluid. A casing defines a portfor the bodily fluid, and a valve mechanism positioned at the port includes amovable valve member.The valve unit further includes a rotor disposed at a first location in thecasing and having an axlewhich turns about an axis of rotation. The rotor defines a plurality ofarcuate, radially flat camsurfaces. Each cam surface occupies an arc about the axis of rotation. Aspring arm unit is disposedat a second location in the casing having a cam follower arm in slidablecontact with the camsurfaces of the rotor and having a resilient spring element applying a closingeffect with the movablevalve member to establish a performance setting for the valve unit. Sufficientrotation of the rotor tochange the cam surface in contact with the cam follower alters the closingeffect with which thevalve member moves relative to the port and thereby alters the performancesetting of the valve unit.
