Reading ;Out reading Ranges of measurement ;-25D~+25D Minimum scale value;—5D~+5D:0.125D ;-5D~-25D,+5D~+25D: 0.25D Cylinder Axis Range ;0~180°Space of readings:1° Prism degree; Model A 0~5△ Minimum scale value 1△; Model B (with prism compensator) Prism basal angle ;0~180°Space of readings:1°;180°~360°Space of readings:5° Eyepiece adjustment ;-5D~+5D Measurand lens Diameter ;Φ16~Φ80mm Dimensions ;226mm(L)×150mm(W)×390mm(H) WeightModel A 3.7kg; Model B (with prism compensator) 3.8kg Lamp of illumination/Power 220V / 110V 15W