Typically the first stage of most reverse osmosis systems.
This is 5 micron sedimentary filter. It has an extra high capacity and is durable.
Full size Polypropylene Filters, for the removal of sediments, dirt, sand and rust.
After fitting, disconnect the pre-filter output from your RO housing and allow to flush for 1 hour then reconnect and start processing.
This helps remove any particles from the new filters and protects your membrane and DI resin.