-pump is powered miniature DC motor drive, drive internal mechanical eccentric eccentric motion, driven by an eccentric movement inside the diaphragm reciprocates. Whereby the pump chamber fixed volume of air compression (compression suction port is closed, the exhaust port is formed to open slightly positive pressure), stretching (compressed exhaust port is closed, a negative pressure sucking mouth open), the pumping air intakes with the outside atmospheric pressure difference, at a pressure difference, the gas pressure (suction) into the pump chamber, and discharged from the exhaust port. -pump is mainly used for medicine, gas analysis sampling, instrumentation and other fields. Completely maintenance-free, and no oil pump, do not pollute the transmission medium. Small, stable and reliable, hand-held instrument for pump-priming, low noise, low power consumption. Especially -suitable for high negative environmental requirements. type:DC12V Mini Vacuum Pump Operating voltage: DC9V ~ 14V Rated voltage: DC 12V Current Rating: 500mA Power Rating: 6W Suction capacity: 5L / min Vacuum degree: 65kpa Maximum pressure: 120kpa Noise: Less than 60db Suitable for 4.5-6mm tube. Mainly about the hardness. The largest part of the outer diameter is 6.5mm. Colour:silver + black Material:Metal + Plastic Package Contents: 1 x Vacuum suction pump Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.