管狀物件，帶或不帶凸緣，旨在減少摩擦，並在平行於孔軸線的表面上承載動載荷。必須具有可見或可檢測的潤滑裝置，或可自潤滑。總長度必須超過外徑的25%或本體週邊平面之間的最短距離，但直管狀（無凸緣或肩部）物體除外，其承載面僅平行於孔軸線。包括分成兩段或多段，且承載圓週角不超過180度（3.141弧度）的物件。另請參閱襯套、套筒；墊片、套筒；以及墊圈（經修改）。不含：銷、空心。
zzzy criticality code justification, material controlled iaw ss800-ag-man-010/p-9290 system certification produres and criteria manual for deep submergence systems; critical item for safety and survival of deep submergence research and rescue vehicles as differentiated by special test features reference number differentiating characteristics, bearing,special part name assigned by controlling agency, hatch handwheel and dog assembly,lower lot end item identification
