Overall dimensions, thread sizes of lubricating nipples and limited supply plugs, straight and angled adaptors for 3/8 in UNF and 1/8 in BSP.F threaded items. Button head nipples (hexagon-headed nipples) for use with connectors which slide on the nipple head. Hook-on and thrust-on types. Hydraulic nipples, straight and angle types for use with hydraulic chuck connectors. Materials, case hardening and electro-plating for ferrous items. Locating of check valves. Notes on use of nipples, access clearances, minimum spacings for grouping.