Aerospace spherical plain bearings are available in Loader Slot, Split Ball, PTFE Lined, Long Life, Metal To Metal and Elastomeric Hybrid configurations. Self-Lubricating or lined products work well in applications where lubrication is not practical due to location or application limitations. The most common industry standards for spherical plain bearings is SAE AS81820 (formerly Mil-B-81820) and AS81936 (formerly Mil-B-81936).