First line: 5501a Optics Laser Heads Laser-Interferometer Positioning Systems Choose from large selection optical components system design flexibilityAbstract: .. For directing 9-mm beams, the 10725A, 10726A 10726A , and 10728A 10728A must be used. These are bare optics that require user-supplied mounts. RETURN. ENTRANCE. RETURN. 53.3 mm 2.10 50.8 mm 2.00 21.6 mm 0 .. Tags: cube beamsplitterbeam Tube"Âoptical Pick-Up headLaser Headinterferometerinterfer*5501a*datasheet abstract..