... ,±4,±5,±6,±8,±10,±12,±15,±20,-25,-30WG-III,Diopter compensation: ±1,±2,±3,±4,±6,±8,±10,±15,±20,±25,+40WG-IIIE,Diopter ... compensation: ±1,±2,±3,±4,±5,±6,±8,±10,±12,±16,±20,-25WG-XP,XPB ... ,XPC,Diopter compensation: ±1,±2,±3,±4,±5,±6,±8,±10,±15,±20,±25,+40Although ear specula's diameter varies,it still can ...