For all Observer models.  Observer II and III yield 64x, 160x, and 640x.  Observer IV yields additional 1600x (oil).

For all Observer models.  Allows you to take relative measurements of what you're viewing.

For all Observer models.  The 100x objective yields 1000x power with the standard 10x eyepieces (10x100=1000x).  It conforms to the international DIN standard and has a spring loaded tip.  Immersion oil is required, and a small vial is included.  Note:  The 100x objective may not perform well with tungsten illumination.  A mechanical stage is strongly recommended when viewing at 1000x (see below).

Place the slide into the holder and move it around using the convenient knobs.  A mechanical stage is especially useful, even necessary, when viewing at high powers where very slight movements can lose the view. (Easily fits into the pre-drilled holes on the Observer microscopes.)

The simple polarizer adapts beneath the eyepiece(s).  The simple polarizer helps improve the contrast between clear specimens and the background, thus making it easier to see the specimen details.