The Polyethylene Speed Control Muffler is designed to give fine adjustment to
the low end of the flow range, followed by more coarse control as flow is
increased toward the maximum. The body is made of highly versatile and costeffective
nylon. The adjusting screw is made of high tensile steel and is coated
with electroplated zinc. The S Series muffler reduces decibel levels to an
OSHA approved level.