Patek Philippe CHR 27-70

The CHR 27-70 is a manual-winding perpetual calendar chronograph introduced by Patek Philippe in 1989. It is based on the Lemania CH 27-525 ebauche, a split-seconds chronograph with perpetual calendar. The movement belongs to the CHR 27 caliber family. It was used in reference 5270 and earlier references until Patek Philippe discontinued it in favor of an in-house caliber.