[Introduction] This Citizen Promaster Eco-Drive (Ref. C660-S067634) represents one of the brand’s most advanced multifunction sailing chronographs, combining solar-powered reliability with the robust design expected from the Promaster line. Its gold-tone case, dual analogue-digital display, and professional-grade features make it a highly practical and collectible tool watch. [Historical & Collector Value] Citizen’s Promaster series has long been appreciated by collectors for its technical innovation and purpose-built functionality. Models equipped with the C660 module are particularly valued for their regatta timers, multi-time digital displays, and Eco-Drive technology—features that reflect Citizen’s dedication to professional sports timing. The combination of a gold-tone finish and multifunction sailing dial configuration makes this reference stand out within the Promaster family. Specifications ◇Brand: Citizen ◇Model: Promaster Eco-Drive ◇Reference / Caseback Code: C660-S067634 ◇Movement: Eco-Drive solar quartz (Citizen Cal. C660) ◇Case Material: Gold-tone stainless steel ◇Strap Material: Black rubber ◇Display: Analogue + digital multifunction ◇Functions: 　・Chronograph 　・Regatta countdown timer 　・Multi-time digital displays 　・Alarm, calendar 　・Rotating compass bezel 　・20 ATM / 200 m water resistance ◇Serial Number: 152050777 (as shown on caseback) ・Condition The watch is in good overall condition with signs of normal use. The dial, hands, and displays are clean and fully legible. All functions operate as expected, and both analogue and digital indications are responsive. The case shows minor wear consistent with previous use. The rubber strap is in very good condition. ・Service History All functions have been checked and the watch is confirmed operational. Although maintenance and functional checks have been performed, battery replacement or a full overhaul may be required depending on long-term usage, as stated in the listing. ・Shipping & Customs International shipping with tracking. Buyers are responsible for any import duties, taxes, or customs fees applied by their country.