The two models, which make up the M-Series (M-2, M-3), represent durable, reliable, high quality navigational aids, which perform flawlessly in even the most demanding of conditions. Both models feature a large liquid filled capsule and adjustable declination correction scale. Another convenient feature of the models in this series is the serrated bezel ring, which is easy to turn even in cold conditions while wearing gloves. Due to their easy-to-read luminous markings and magnifying lenses, the compasses of the M-Series are also ideally suited to navigating in conditions of poor visibility.