Letterboxing is an outoor hobby that combines elements of orienteering, art and puzzle solving. Letterboxers hide small, weatherproof boxes in publicly-accessible places (like parks) and distribute clues to finding the box in printed catalogs, on one of several web sites, or by word of mouth. Individual letterboxes usually contain a logbook and a rubber stamp. Finders make an imprint of the letterbox's stamp on their personal logbook, and leave an impression of their personal stamp on the letterbox's logbook — as proof of having found the box. Many letterboxers keep careful track of their "find count".