Polyester Filter Bag 1. Ideal medium for liquid filtration 2. ... liquid bypass occurring due to needle holes.Type Pocket Filter Usage Liquid Filter Certificate ISO Liquid filter bag 1. (micron): 1, 5, 10 ... ES-1, ES-2, ES-3, ES-4 Liquid filter bag Filter bag filter ability(micron): 1, 5, 10, 25, 50, 75, ... 100, 150, 200 International standard filter bag parameter: ES-1, ES-2, ES-3, ES-4