Postkassetrimmen is a free iPhone app developed by Mats Byrkjeland in the lifestyle category, specifically targeting health and fitness enthusiasts. The app allows users to go on hiking trips, check-in at various locations, and earn points for their activities.

With Postkassetrimmen, users can collect mountains as they hike. By checking in when they are within 75 meters of a point on the map, users can contribute to their own statistics. The app provides an overview of the number of hikes completed, the number of different mountains visited, and the total elevation gained. Users can also compare their progress with others on the leaderboard.

In addition to the standard challenges, known as "Trimmar," organized by hiking clubs or Postkassetrimmen, users can also set personal goals called "Bragder." These can be anything from hiking to mountains over 1000 meters, visiting mountains in multiple municipalities, or exploring mountains with "nut" in their names. These achievements provide users with additional motivation to challenge themselves and explore new hiking destinations.

Postkassetrimmen is the perfect app for hiking enthusiasts who want to track their progress, compete with others, and stay motivated on their fitness journey.