Maxon 32731 Sleeve 318518 761 Variable pitch designs allow technicians Variable pitch designs allow technicians to adjust the fan speed on site to compensate for ductwork restrictions or changes in static pressure without changing the motor speed or pulleys Precision Color Correspondence: Eliminates guesswork by providing an exact York Caribbean Blue match for professional equipment restoration the 310SS alloy used in this sleeve is specifically chosen for its ability to maintain a protective oxide scale in high temperature oxidizing environments this 310SS discharge sleeve is essential for maintaining proper flame shaping and protecting burner internals from thermal stress