Fully integrated perpetual calendar developed for MB&F by Stephen McDonnell, featuring dial-side complication and mechanical processor system architecture with inbuilt safety mechanism. Manual winding with double mainspring barrels. Bespoke 14 mm balance wheel with traditional regulating screws visible on top of the movement. Superlative hand finishing throughout respecting 19th century style; internal bevel angles highlighting hand craft; polished bevels; Geneva waves; hand-made engravings. Power reserve: 72 hours Balance frequency: 18,000bph / 2.5Hz Number of components: 581 Number of jewels: 41 Functions/indications: Hours, minutes, day, date, month, retrograde leap year and power reserve indicators Case Material: stainless steel. Dimensions: 44 mm x 17.5 mm Number of components: 69 components Water resistance: 30 m / 90′ / 3 ATM Sapphire crystals Sapphire crystals on top and display back treated with anti-reflective coating on both faces. Strap & buckle Brown hand-stitched alligator strap with stainless steel folding buckle.