Internal CADviewer 4.2   
by Cadhedral   

INTERNAL CADVIEWER is FREE DWG viewer that can be launched
directly from your AutoCAD. With this AutoCAD add-on you can browse,
view or open drawings stored on your computer or CD-ROM(e.g. DWG catalouges).

You can view or open next, previous, first or last drawing in the current
folder(folder of the current drawing).

You can also view a sequence of drawings in slide show with defined time delay.

Thumbnail mode gives you the ability to view multiple drawings simultaneously
in reduced size. Drawings can be open directly from their thumbnails.
There is also thumbnails slide show available.

Open button enables you to select another folder with DWG files or you can
open another drawing. Selected folder can be added to the favorite folders.