Lumax LX-4807 Gold/Silver 6mm x 1 (Metric) 8 Piece Grease Fitting Assortment Passivated finish for maximum protection from corrosion Heavier wall thickness for extra strength Stress relieved and tempered carbon steel spring Ball check in head prevents dirt from getting in Fits LX-3301 (4 piece), LX-3303 (2 piece), LX-3305 (2 piece)