Grease fitting kits typically include straight, angled (such as 45 degrees and 90 degrees), and sometimes needle-type fittings. The thread sizes of the fittings vary, commonly featuring SAE (Society of Automotive Engineers) and metric sizes. For instance, the kit may offer fittings in sizes such as 1/4 inch, 1/8 inch NPT (National Pipe Thread), M6, M8, and M10.