Nauticalia

This star identifier looks and works very much like a torch, but the light beam it projects is overlaid with a star map, and what might be a "focussing ring" is actually a time/date adjustment. So, if you direct it against a light-coloured wall or ceiling in the dark, it can show you the names of 23 major stars and 30 constellations that are visible at that time, applicable to latitudes between 30 and 60 degree in the Northern Hemisphere.
 
Its tough aluminium casing is anodised for a long lasting finish and measures just 6" long - comfortably pocket-sized.

Uses three AAA batteries (see ref: 93194 below).