4 Eye is a sort of Pleated Filter Cartridge with a diameter of approximately 183mm.This end cap is available only in ABS Plastic. This unique sort of 4 Eye filter cartridge can be mounted from both the top and bottom sides of the cell plate.It has a very steady arrangement of 4 bolts which could keep the filters in place very well and the chances of bypass or leakage could be negligible. Below  are the various configurations in which these filter could be made.