The Nauticalmart Special Antique Brass 4-inch sextant has a slow motion control to allow fine adjustment of the elevation angle. A built-in magnifier can be swung into position to assist in reading the German Silver vernier scale, and there are six swing-arm filters. These models are perfect for the collector or the beginner interested in learning celestial navigation. A beautiful handcrafted hardwood storage and display box made out of a high quality smooth finish hardwood comes with this antique brass sextant.