Trial Frame Adjustable Rotating for Trial Lenses,FULL METAL.Range of PD adjustments : PD of both eyes: 48-80 mm Left or right PD: 24-40 mm Minimum Calibration Value : 1 mm Axial calibration on each disc : Left disc: 120' -0' -135' Right disc: 45" -180' -60', Axial calibration increases counter clockwise along the lens frame axis, and the calibration distance is 5' Inner diameter of lens frame : 0 32.5 mm The Number of lens, which can be inserted into lens frame simultaneously : 4 pieces Degree of lens rotating around optical axis in the lens frame : 360" Non- parallelism degree between lens optical axis and lens frame's geometric axis : <2.5' Non-concentricity between lens optical center and lens frame geometric center : <0.5mm Displacement of lens in relation to position of lens frame geometric center : <0.3 mm Range of nose pad adjustment: Length : 0-14 mm; Angle: 0" -30" Range of left or right lens frame leg's length adjustment : 98-135 mm Maximum interval between left and right lens frame legs : 200 mm Weight : 72 gms.