The pinnacle of Patek Philippe's Advanced Research programme. The 5550P unites a perpetual calendar with the complete Oscillomax trinity, Spiromax hairspring, Pulsomax escapement, and GyromaxSi balance wheel, all crafted from Silinvar, Patek's proprietary silicon-based material. Housed in a 37.2mm platinum case, this is watchmaking at the intersection of centuries-old tradition and twenty-first century precision engineering. Limited to just 300 pieces, produced in 2012, and presented here in unworn condition with its complete full set. A cornerstone piece for the collector who understands exactly what they're acquiring.