IMPROVED FLUID RESERVOIR PISTON

摘要

A piston comprises a first member (1404) and a second member (1201). The fir st member (1404) has an external proximate side and an external distal side. The external proximate side is adapted to contact the fluid and is made of a material having a first stiffness. The second member (1201) has a first side and a second side and is at least partially disposed within the first member (1404). The first side of the second member (1201) is adjacent to the external proximate side of the first member (1404) and is made of a material having a stiffness which is greater than the first stiffness.