Die-cast aluminum case;Oil-impregnated, self-lubricating bushings;Molded, convoluted diaphragms for smooth operation and long life;Rigid, reinforced flag rods for positive alignment and sustained accuracy;Graphite-filled phenolic valves to minimize wear;Long-life, low friction, grommet seals;Single coat polyester primer with high solids polyurethane top coat;Security seals that indicate tampering