Technical Specifications Category Specification Model 657-40 Type Pneumatic Spring-and-Diaphragm Linear Actuator Action Spring-Return (Single-Acting) Spring Code -40 Bench Setting The "-40" code corresponds to a specific air pressure range. A typical bench setting for a -40 spring is 3-15 psig, meaning the actuator starts moving at ~3 psig and reaches full travel at 15 psig. Standard Stroke Available in various strokes (e.g., 3/4", 1-1/2", 2-1/2"). The specific stroke is defined by the full model number. Thrust Output The thrust is determined by the diaphragm size and the air pressure. The 657 series provides a range of thrust outputs for different valve sizes. Air Connection 1/4" NPT Diaphragm Material Nitrile (Buna-N) is standard. Yoke Material Cast Iron (standard) Temperature Limits Standard: -20°F to +180°F (-29°C to +82°C).