Common cylinder operation is controlled by a pneumatic valve, when the need to open the pneumatic valve to control one end of the cylinder intake and exhaust at the other end, the need to close the pneumatic valve will control the other end of the original intake end exhaust, so every action has exhaust sound. Pneumatic valve is also a spring return is only one end of the intake to open the valve, Níl ach sceite aer dúnta le taobh an earraigh atá freagrach as a dhúnadh . Is é gníomh an chomhla seo ceann de na fuaimeanna sceite tánaisteacha .
