Dixon Boss B37SC Plated Iron Hose Fitting, Wing Nut Cap for 3" Boss Holedall Fittings Cap for covering the end of a wing nut Connects to a wing nut threaded connection Plated iron for strength, malleability and ductility, high magnetic permeability, and resistance to corrosion Klingersil C-4401 washer for high heat resistance, chemical stability, high torque retention, and anti-stick properties For non-pressure applications