The external Sampling Pump is for most diffusion Gas Detector. The main function of this device is used to check if there is gas leakage when measuring the gas underground manhole. Among the other important features includes an excellently durable industrial pump installed, a simple structure to install locking, automatic checking of chocking, operating temperature -20ºC ~ 50ºC, 1.5V AA size Alkaline battery, and more than 10 hours battery lifetime.