This document has been declared "Stabilized" and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability or technical requirements. New technology may exist. This SAE Aerospace Information Report (AIR) discusses the terminology, types, method of manufacture and chemistry of fine wire meshes used for filtration of hydraulic, lubrication fuel systems, and similar applications. Information contained herein may be used for quality assurance testing to insure that a high performance filter grade wire mesh is acceptable for use in an aerospace application. This document pertains to meshes as coarse as 4 x 4 wires/cm (10 x 10 wires/in) or coarser, as well as to meshes as fine as 155 x 1100 wires/cm (400 x 2800 wires/in) or finer. Fine wire meshes refer to all wire meshes used for filtration, but also the coaser meshes used as a backup or supporting material.