 The core activities of the Silva Group consist of design, development, manufacture of compasses for land and sea and sales of compasses, GPS and outdoor instruments, headlamps, binoculars and other electronic navigation equipment.Silva of Sweden AB has manufactured a wide variety of portable compasses for recreational, hiking, scientific, and marine uses over the years, including simple protractor or baseplate compasses like the "Field", "Expedition 3" (formerly the "Ranger 3"), and "Expedition 4" to more sophisticated sighting compasses such as the "Expedition Model 54" and the Silva "SightMaster" line of surveying compasses.Silva's "Expedition 15T", "Expedition TDCL", and "Expedition S" are modernized versions of the original Type 15 "Silva Ranger", itself a development of the "Model 1939" that incorporated a liquid-damped capsule with a sighting mirror that doubled as a protective cover.