Three parts: Dial, inner case-ring, and inner case-back, all made in the same soft iron alloy, protect the movement and improves the current Swiss standard in magnetic resistance by 10. Meet the new ref. 5303, from professional dive watch to Amagnetic Diving Chronometer. #serica #sericawatches #watchmaking #sportswatches #goingtheextramile #automaticwatches #refinedsimplicity #toughwithcharm #swissmade #5303 #serica5303 #COSC #chronometer #amagnetic #antimagnetic