We need you to provide precision, material, size, quantity, and these are the basic data. 

If you are buying a filter cartridge, you also need to specify the connection method, the inner diameter and outer diameter of the end. 

If you are purchasing a filter, you need to explain the shell material, filter material, filtration accuracy, working pressure, flow size, working temperature, connection method, filter media, whether it can be self-cleaning or backwashing.