This SAE Recommended Practice shall cover mechanical- readjust stroke indicators for actuators with visible exposed pushrods and electrical-readjust stroke indicators for all air-brake actuators. This device shall indicate the foundation brake(s) may require adjustment or service when inspected per vehicle manufacturer's procedures. A measurement shall be made to determine actual stroke measurement for any system not factory calibrated. Stroke indication accuracy of an air-brake actuator can be assured only when all of its components are supplied by the original brake actuator manufacturer. Purpose This document establishes design guidelines for air-brake actuator stroke indicators.