395Pcs Stainless Split Spring Washers Sealing Ring For M4 - M12 Bolts & Screws
Size: M4 M5 M6 M8 M10 M12. M12 x 15 PCS. M4 x 120 PCS. When tightened, their unevenly split ends bite into unhardened nuts and bolts for a tighter grip than curved or corrugated washers, but only for applications with clockwise rotation.