It compresses (closing the compression suction port, forming a slight positive pressure at the exhaust port) and stretches (closing the compression exhaust port, opening the negative pressure suction port) to suction and expel air.
eBay
12V 24V DC 555 Micro Vacuum Low Noise Electric Pumps Vacuum Coating Machine Air Pump Fish Tank Oxygen Pump Silent Air Pump
Aliexpress UK
Maximum vacuum: >0.085MPA. Number of lb head: Negative pressure 1. Net weight: 7.5KG. Pumping rate: 30L/MIN.
eBay
Mini Vacuum Pump DC2-5V 85mA Micro Air Pump 650ml/min Flow Rate -400mbar Vacuum Degree Small Air Pump Gas Detect Sampling Pump
Aliexpress UK
Ultimate vacuum: - 77KPA. 1 x Micro Oilless Vacuum Pump. Oil less vacuum pump is a machinery vacuum pump that running without any oil for lubrication.
eBay
Mini Vacuum Pump DC2-5V 85mA Micro Air Pump 650ml/min Flow Rate -400mbar Vacuum Degree Small Air Pump Gas Detect Sampling Pump
Aliexpress UK
Maximum vacuum degree: up to 0.085MPA. Maximum vacuum degree: up to 0.095MPA. Maximum vacuum degree: up to 0.092MPA. Net weight: 10kg. Power: 160W.
eBay
-85kpa 40L/min Mini DC Vacuum Pump 12V 24V Negative Pressure Suction Piston Cupping Small Vacuum Pump
Aliexpress UK
Item Type: Oilless Vacuum Air Pump. Low Noise: The power of the air pump is 1/4HP, and the is ultra quiet, there is only 50dB, will not disturb others when working. High : Adopt oil lubrication and double cylinder piston structure, the air pump has high pressure and large flowing, which provides 35‑40L air per minute.
eBay
Water Pump Self-priming Pump 5V Water Pump USB Small Pump Vacuum Mini Elecctric Water Pump Replacement 4L/min
Aliexpress UK
Equipped with bracket for easy fixation. The eccentric motion drives the internal reciprocating motion of the diaphragm. Suction: 5L/min. Item Type: Vacuum Pump. 1 x Vacuum Pump. Vacuum Degree: 65kpa.
eBay
Water Pump Self-priming Pump 5V Water Pump USB Small Pump Vacuum Mini Elecctric Water Pump Replacement 4L/min
Aliexpress UK
Oil-less piston vacuum pump. -Pvdf run litre+ plus easily and hotter than nylon with no risk of microtears. Kvac vacuum pump. Max vacuum 80 torr/80kpa. Air flow 168/206 Litres a minute. VACUUM FILTRATION FLASKS (500ml £19)(1000ml £25).
eBay
Water Pump Self-priming Pump 5V Water Pump USB Small Pump Vacuum Mini Elecctric Water Pump Replacement 4L/min Drop Ship
Aliexpress UK
Laboratory Electric Oilless Diaphragm Vacuum Pump. Diaphragm&Vales. Our main products including magnetic stirrer,heating mantle,pipettes,centrifuge,vortex mixer,vacuum pump etc. Vacuum Pump. Vacuum Pump Technical Data.
eBay
Creality official 3D Printer Filament Vacuum Storage Kit,40 x 40CM Reusable Vacuum Storage Bags with Electric Pump Dust Proof
Aliexpress UK