... ,±3,±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 ... 2.5v/0.3A) Power Supply:1.5V x 2 "C"Type ENT Diagnostic Set WG-I