Frederique Constant · Index
Strap for Index Automatic Chocolate
Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.
Lug width
20mm
Lug width20 mm
Case diameter40 mm
ReferenceFC-303C5B4
FamilyIndex
MovementFrederique Constant caliber FC-303
Hours, Minutes, Seconds | Date
CaseStainless Steel
Straps for the Index FC-303C5B4
Selected for the 20 mm lug width · workshop selection
Vintage Black Calfskin Leather Strap€80
Hammered Calfskin Strap Light Blue€98
Hammered Calfskin Watch Strap Green with Ecru Stitching€98
Vintage Olive Green Calf Leather Watch Strap€80
Hammered Black Calfskin Strap — Ecru Stitching€98
The Index FC-303C5B4, seen from the bench
The Frederique Constant Index Automatic Chocolate FC-303C5B4 is a 40mm stainless steel case watch with a lug width of 20mm. It features the FC-303 automatic movement visible through a transparent caseback, offering hours, minutes, continuous seconds, and date window. Water resistance is 30 metres, with a fixed bezel, screw-down crown, and sapphire crystal with anti-reflective coating. The watch exemplifies contemporary Swiss watchmaking, balancing formal and casual elegance through its proportioned design.
The next step
The right strap isn't chosen. It is built, together.
From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.
Request an appointment →Casati Milano · Via XX Settembre 15, Milan · by appointment only