The 40 Series pneumatic (3-15 psi) and 41 Series electro-pneumatic (4-20mA) rotary positioners are advanced control devices which provide un-paralleled stability in difficult environments. Rugged aluminum housing with a triple corrosion-resistant interior and exterior coating that resists harsh environments. Bleed pilot valve reduces air consumption by more than 50%. Precise calibration with simple SPAN and ZERO adjustments. Unique magnetic 4-20mA I/P converter provides automation compensation for supply pressure, atmospheric pressure and ambient temperature changes, and is unaffected by electromagnetic fields. Precision zero-hysteresis coupling system provides superior accuracy and repeatability by eliminating “slop”. Stainless steel guages standard.