Grease nipples or zerk fittings are used for injecting lubricants into bearings and other applications using a grease gun. Specifications: Standard : DIN 71412, IS 4009-2, DIN 3404, IS 4009-1 or as per customer spec Material : M.S., EN 1AL (free cutting steel), 11SMnPb30, S.S. 303, S.S. 316 Hardness : Minimum 500 HV for nipple head Thread : parallel, taper Surface treatment : clear (blue) zinc plated, yellow zinc plated, olive green zinc plated, zinc trivalent plated