Features 1、Suitable for students or  professional use. 2、Made of high quality material, durable and has a long service life . 3、 Precise workmanship, humanized design, adjustable height of nose holder, more comfortable to wear. 4、 Lightweight and comfortable for your patient. 5、 Large capacity, the left or right frame can hold 4 lenses at the same time. Specification Condition: 100% Brand New Item Type: Optometry Frame Material: Aluminium Alloy Color: As shown in the picture Range of PD Adjustments: PD of Both Eyes: 50-80mm / 2.0-3.1in, Left or Right PD: 25-40mm / 1.0-1.6in, Minimum Calibration Value: 1mm. Axial Calibration on Each Disc: Left Disc: 140°-0°-130°, Right Disc: 50°-180°-40°, Axial calibration increases counter clockwise along the lens frame axes, and the calibration distance is 5°. Inner Diameter of Lens Frame: Φ32.5mm / 1.3in. The Number of Lens Which Can be Inserted Into Left or Right Lens Frame Simultaneously: 4 PCS Degree of Lens Rotating Around Optical in the Lens Frame: 360° Package List 1 x Optometry Frame 1 x Instruction Manual