AUFO Portable Survival Compass with Keychain Key Ring for Hiking and Camping Material: Alloy Silver The green line is the reference line. A rudder compass pendant key chain. Compass diameter: Approx. 1.97inch/5cm. Total length: Approx. 6.89inch/17.5cm. A new set of classic pocket watch style compass, old fashion and harmonious, portable design, convenient to carry. Compass is easy to install and operate; you can take it anywhere you go.