High volume delivery at low pressure makes pumping chemicals safer. Double action means you get delivery on both the up, and down stroke. Two fingers on the handle is all the energy required to pump viscous fluids or harsh acid or alkali cleaning chemicals. The unique patented pumping principle means no parts that wear. Made from polypropylene and low density polyethylene, that meet FDA standards, pumps can be used with confidence with food contact. Resistant to a wide range of acid, alkaline, caustic, and chlorine based chemicals, oils, crop chemicals, diesel and liquid fertilizers. Not to be used with strong solvents, highly flammable liquids or for pumping petrol (gasoline). 20mm spout opening fits 3/4" ID or 1" OD extender hose. USe the 90033 Pour Spout Adaptor (sold separately) with this pump to connect to pour spout lids. Seals are LDPE.