FixtureDisplays 100PK 0.31" (8mm) Split Lock Spring Washers Screw Gasket Galvanized Steel 18207S-M8-100PK.M8 Inner Size Galvanized Steel Spring Washers. Suitable for mounting electronics, machinery, car models, model aircraft and other supplies. Washers are normally used to distribute loads of threaded bolts, screws and nuts evenly as the fastener is tightened. Intended for the general use under the head of a bolt or nut.Measures 0.51" (13mm) in outter diameter, 0.31" (8mm) in inner diameter, 0.1" (2.6mm) thickness.