Frederique Constant Watch Slimline Perpetual Calendar FC-775N4S4. The Frederique Constant watches Slimline Range consists of some of the evergreens in our collection. These timepieces include latest technology, while maintaining their same successful, stylish and clean designs. The Frederque Constant Slimline, a tribute to fine Geneva Watchmaking, uniting style, elegance and high quality at sensible prices.