SS2121 measurement microphone is 1/2 inch high-quality prepolarized free field microphone, with preamplifier housing made of stainless steel material, suitable for acoustic testing requirements in various occasions. The microphone kit has obtained explosion-proof certificate issued by the Testing Center of Coal Science and Technology Research Institute Co., Ltd. It is suitable for all explosive gas environments except coal mine gas environments, and its explosion-proof mark is Ex ia IIC T6 Ga.