Abstract: A unitary, elastic muffler assembly includes an arcuate, channel-shaped, sound-muffling section having opposite ends bridged by an integral elastic band. The assembly is telescoped over the tubular housing of a pneumatic device into a position to receive spent working fluid exiting from housing vents into the central area of the sound-muffling section wherein the fluid divides and follows arcuate flow paths defined by the tubular housing and the sound-muffling section through sound-attenuating material to exhaust ports located in the end walls of the sound-muffling section. The movement of the fluid along the defined flow paths of a total arcuate extent substantially greater than 90.degree. diminishes the noise level of the spent working fluid below 90 dBAs. Also, the fluid movement away from the housing vents avoids causing icing up or significant reducing of the operating efficiency of the pneumatic device.