The single 4 "round head is made of T-304 stainless steel and TIG welding, with stainless steel mesh wrapped hole core and high-quality glass fiber packaging. The small perforated plate muffler is generally made of pure metal plate with a thickness of less than 1mm. The drill with a hole diameter of less than 1mm is selected on the plate for drilling, and the drilling rate is 1% - 3%. Choosing different punching rate, plate thickness and cavity depth can control the spectrum performance of the muffler and achieve good silencing effect within the required frequency range.