The Tudor Black Bay GMT reference 79830RB, known to collectors as the Pepsi, represents Tudor's modern take on the dual-time-zone tool watch tradition and stands as one of the most successful releases from the brand's post-2016 manufacture-movement era. Introduced at Baselworld 2018, the Pepsi GMT pairs the heritage-inspired Black Bay aesthetic with a true caller-style GMT complication, the local hour hand independently adjustable to allow rapid time-zone changes without affecting the running of the minute and second hands. The 41mm stainless steel case carries a bidirectional 24-hour rotating bezel with a matte burgundy and blue anodized aluminum insert, the two-color execution distinguishing daylight from nighttime hours and giving the reference its nickname. The domed black dial features applied luminous markers, Tudor's signature snowflake hands, and a red GMT hand tracking the second time zone. Powered by the Tudor Manufacture Caliber MT5652, a COSC-certified flyer GMT movement with a 70-hour power reserve, silicon balance spring, and 28 jewels at 28,800 vibrations per hour. Water resistant to 200 meters, fitted on a brushed steel oyster-style bracelet. 2021 production, pre-owned with full Tudor box and papers.