Explorer Dial - Instrument to measure distances inspired by Thales theorem.
Untight the strap to its maximum and straighten it with your arm in order to have an optimal measure. Try to stabilise your arm with the help of object around you (rock, bench, friend's shoulder). Close an eye, hold your breath and aim at the landmark (5m or 2m) defined. Get the top and bottom of the landmark through the dial by sliding the button and simply read the graduation.
Anodized aluminium and polycarbonate.