In response to continuing demand, Edmund Optics developed these eyepiece cell assemblies for OEM and system integration. The flexibility of the design makes these highly effective as either eyepieces or magnifiers. The 9X and 12X cells offer a three-element Kellner-type design, providing excellent aberration correction. The 6X model has a precision single-element DCX lens. Prescription information available upon request. Please complete a Request for Prescription Form.Lock Ring has internal 1"-20 TPI thread in order to thread onto one of the TECHSPEC® Eyepiece Cell Assemblies for fixing the focus position of the Eyepiece within the Eyepiece Cell Adapter. Lock Ring is 4mm long and has 29mm outer diameter.