BINOCULAR OBSERVATION HEADSiedentopf observation head inclined at 30° rotatable at 360°.Diopter adjustment ring on ocular tube. Interpupillary distance from 55mm to 75mm. EYEPIECE : PL 10 X/18mm (Paired)OBJECTIVES(STRAIN FREE)E Plan Achromatic 4X E Plan Achromatic 10X E Plan Achromatic 40X (SL)MECHANICAL BODY (A) U-shaped stand. Co-axial focusing system with PRE-FOCUSING LEVER & TENSION ADJUSTMENT RING. Coarse 25mm moving range fine minimum reading is 0.002mm (B) Quintuple nosepiece revolves on ball bearing with positive indexing soft rubber knurled Grip on nosepiece. INTERMEDIATE TUBEBuilt-in analyzer removable from optical path. Analyzer can be rotated by 900 with a vernier reading to 6’. CIRCULAR ROTATING STAGELarge 135mm diameter circular rotating (360o) stage utilize ball bearing i.e. graduated in 1o increment and include a vernier reading to 6’. CONDENSER Condenser with Iris Diaphragm & Filter with N.A. 1.25COMPENSATORGyps18 (dia. 18mm,1st order red compensator plate, 550 nanometers) Mica 1/48 (dia.18mm, 147.3 nanometers) Quartz Wedge(12X28mm, I-IV)POLARIZER WITH LOCK Can be rotated 360o and can be removed from optical path.ILLUMINATOR SYSTEMThe 6V/20W halogen bulb (Philips 5761) Koehler illumination system pre centered. Continuously variable intensity control.STANDARD ACCESSORIES6V/20W Halogen tungsten bulb. Blue, Green & Yellow filters. STYRO FOAM molded pack.