ROLEX, REF. 116520, DAYTONA, A STEEL CHRONOGRAPH WRISTWATCH ON BRACELET CIRCA: 2015 CASE MATERIAL: Steel CASE DIAMETER: 40mmSERIAL NO’: R704Z511BRACELET MATERIAL: SteelBRACELET SIZE: 170mm Approximate Overall Length DIAL: White MOVEMENT: Automatic FUNCTIONS: Chronograph BOX: YesPAPERS: YesACCESSORIES: Rolex Guarantee, Rolex Presentation Box, Product literatureA modern day icon. The Rolex Daytona Ref. 116520 houses the caliber 4130, made by Rolex. The caliber 4130 is Rolex’s first in house chronograph movement, replacing the Zenith based ebauche. The new movement was debuted in 2000, updating the Daytona reference 16520 to reference 116520, marking the brand’s first foray into in house chronograph caliber production.