The trial frame has the ability to accommodate up to four pair of lenses Easier to use and easier to wear Easily changeable cylinder Fully adjustable temple length and nose rest Horizontal and vertical bridge adjustment new optical trial lens frame, provides the ability to refract even the most difficult prescriptions and offers all the adjustments to a proper and comfortable fit onto your patient. Description: The trial frame has the ability to accommodate up to four pair of lensesSeparate PD adjustment for each eye Individual adjustments for temple length Adjustment for rotating cylinders Scales with large numerals Material: metal or plastic Lens holder with a diameter of 38mm Wide Range of PD Adjustments: 48 - 80mm Package Content:1xtrial frame Note:Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.