Rocker series lab vacuum pumps are driven by Piston, without the need of lubricant, regular oil changes and maintenance; with no oil pollution. Chemical Resistant Vacuum Pump Chemker pumps are PTFE-made chemical resistant diaphragm vacuum pumps that can be widely used with hard acidic, basic and solvent vapors. With the ROCKER philosophy of resource-saving and user-safety-first, Chemker™ pumps are designed to be cost-effective, quiet and safe..https://www.gaiascience.com.sg/productcategories/vacuum-pump-laboratory-essentials