Product Description: The BEI Sensors/Sensata part 01091-079 Is a Model HS20 rugged hollow-shaft encoder designed with harsh environments in mind. This optical encoder can be used where lighter duty encoders are not suitable or cost effective. The compact design makes it easy to incorporate into tight installations and it is well-sealed to stand up to dust, dirt, and splashing liquids. Other features include dual preloaded bearings for longevity and stability, differential line driver outputs for noise immunity and a standard, Euro-style 8-pin (M12 x1) sealed connector for easy connectivity. A specially designed, non-marring shaft clamp allows for easy installation and eliminates shaft damage should you need to reinstall or reposition the encoder on the shaft. Model HS20 is ideal for small motor applications and a number of harsh applications including off-highway agriculture and construction equipment.