Alemite 1641-B features. Dirt excluding ball check. Exceeds 72 hour salt spray test. Trivalent zinc plating. RoHS compliant. Hex size of 5/16". Straight configuration. Overall length of 35/64". Shank length of 3/16". Alemite 1/4 inch 28 Taper Thread Fittings are used on most cars and trucks, as well as many industrial machines. It is recommended that SAE-LT taper threads be assembled into 1/4 Inch 28 UNF, Class 3B, straight threaded holes having a modified maximum minor diameter of 0.2151 inch, to ensure 75 percent minimum thread height.