Biprism Assembly:- The Complete unit comprises of following components :

a) Optical Bench: - Twin bar 150 cm long having two sliders with fine coarse motion and two sliders without coarse motion Uprights to hold 1/2" stems.
b) Lens Holder: - One spring action lens holder.
c) Micrometer Eye Piece :- The carriage of eye piece moves for lateral motion on a traded screw with the help of graduated micrometer head All metal sturdy construction fitted with 10 x complete set eye piece.
d) Optical Slide: - Having well ground stainless steel jaws, spring action type.
e) Biprism Holder: - It has fine radial motion separated by a fine pitch screws. Complete assembly as described above.
f) Biprism Assembly: - Same as above but having stainless steel bars in place of steel bars in optical bench.
g) Biprism assembly: - Same as above but optical bench having both the bars covered with brass pipe.
h) Fresnels Biprism: - Low angle in velvet lined case 1) 30 x 40 mm. 2) 40 x 50 mm.
i) Biprism Assembly : Same as above but without optical bench