Another nice advantage of the Observer's light is that the bulb is a common desk lamp bulb which can be found in most larger home centers, like The Home Depot. The Observer also includes an easily installed mirror, that permits you to use your scope outdoors without electricity. Simply unscrew the light lens, and install the mirror. The Observer IV is like the Observer III in every regard except that it adds a fourth objective, 100xr, to the nosepiece, yielding 1000x. This is an oil immersion lens.
Immersion oil is included.
The 40xr and 100xr objectives are retractable to protect your lenses and slides should they come in contact. It serves those who want the convenience of dual eyepieces, but yet who don't want the added expense of a full professional model. The Observer IV Binocular is identical in every way to the popular Observer IV, with the exception that it has binocular eyepieces. We'll be happy to help in any way we can. Additional accessories available.