This International Standard specifies the essential dimensional features of expander/segment oil-control rings, without providing a complete product description (because expander-spacer design varies from piston-ring manufacturer to piston-ring manufacturer, the interaction between the manufacturer and the client will determine specific design details). This International Standard applies to expander/segment oil-control rings of nominal diameters ranging from 40 mm to 125 mm for reciprocating internal combustion engines for road vehicles and other applications. It also applies to piston rings for compressors working under analogous conditions.