PROLUBE 46006 ¼” – 28 SAE LT Grease Fitting (5 Pack). Manufactured to the most stringent quality standards – TS16949 approved manufacturing. Fitting profile & dimensions are accurately controlled & conform to SAE, DIN, BS, JIS & is standards. Grease fittings are heat treated to SAE J534 specification with hardness on greasing end to a minimum of 83 on Rockwell 15N scale with a case depth of 0.005” (0.13 mm) to 0.009” (0.23 mm). steel fittings are plated in yellow zinc with a plating thickness of 0.0002” (5 microns) confirming to SAE J534 specification & have a guaranteed salt spray life of over 72 hours to red rust.