It took over 600 hours of research to develop the case on this Audemars Piguet Royal Oak Perpetuel Calendar Watch. It appears to have been worth it. The matte black brushed finish on the 41mm ceramic case is resistant to scratches, temperature, and age, so it pairs well with the moonphase indicator, which only requires correction once every 125 years. The 5134 movement also powers the date, date, month, leap year, hours, and minute functions, all of which appear on the slate gray "Grande Tapisserie" dial. It's finished with a matching ceramic bracelet with a titanium clasp.