Suunto tandem Compass Clinometer, with magnifier, and Tritium. Finland. This tool dates to the 90's, features Tritium light source for both tools. Tritium is a radioactive isotope that glows in the dark, and allows this tool to be used at night. please note that the Tritium light source still glows, but is getting weak. The Compass and Clinometer are both accurate to 1 degree. The liquid in the compass capsule is starting to oxidize, and still functions properly. Buyer pays return shipping if returned, thanks for viewing.