Made of light-weight metal & plastic. Holds 5 trial lenses. Holds standard 1.5″ (38 mm) trial lenses. Independent right and left adjustment of PD 1.9″ to 3.15″ (48-80 mm). Bridge height and inclination operate by a rack and pinion. Sides adjustable for length and angle. Compatible with Fresnel Prism Trial Lens sets. Low-set hinges allow easy insertion of lenses into the rear lens cells. With Vertex distance scale.