Size Reference-- Package includes 100 pcs syringe filter including 2 colors(50pcs/color), measures in about 0.71"(18mm) in diameter, 0.83"(21mm) long Uniform Pore Size-- Syringe filter with uniform pore size, high porosity and high retention efficiency. Syringe filter diameter: 18mm, Pore Size: 0.22um(green), 0.45um(white) Hydrophobic Membrena-- Needle syringe filters have membrane, the naturally hydrophobic, it with broad chemical compatibility and strong chemical stability and inertia, strong hydrophobicity No Sterile Syringe Filters-- Syringe filters with membrane and housing is made of high quality nylon material and unique threaded interface design, non-sterile, no adhesive, no contamination of the sample Wide Usage-- Needle Syringe filters are broadly used in filtration of various organic solvents, as well as the filtration of strong acid and strong alkali solutions. And the syringe filter also suitable for gas filtration