The front of the lock plate is signed "A BERLIN" above the frizzen spring and "I.C. SAPS" below the spring. Blade front sight with raised section for a dovetailed rear sight. There is a pressure relief valve under the barrel, which is tripped by an auxiliary lever inside the lock to activate the air release, thus propelling the projectile (from the outside, the only clue to this not being a flintlock is the lack of a touch hole for powder ignition!). A 12 1/2 inch retractable iron rod (within an air piston) is fitted inside the butt. Full length walnut stock with relief carvings flanking the cheekpiece and around the upper tang. A hollow brass tube is visible on the right side of the butt, probably an additional pressure release valve.