Technical specifications: trial frame model rtf-10, as per the specifications given below: the adjustable trial frame is a light weight trial frame with aluminium & stainless steel sidesthe cells are spaced to accommodate reduced aperture lenses onlyaccommodate up to 8 pieces 38mm trial lenses and it permits smooth & easy manipulation of bridge & p.d.fully adjustable temple length and nose rest.easily changeable cylinder axiswide range of pd adjustments from 48mm – 80mm.