Universal Trial Frame, black, light-weight metal / plastic, for 5 pair of lenses, independent right and left adjustment of PD 1.9" - 3.15" / 48 - 80 mm. Bridge height and inclination operates by a rack and pinion. With vertex distance scale. Sides adjustable for length and angle. The low-set hinges allow easy insertion of lenses into the rear lens cells. For lenses ø 38 mm. Slip-on Roary Polarizers. Easily attached to the Universal Trial Frame.