A highly sought-after first-generation Certina DS "Turtle Back" (Double Security) from approximately 1964. This model is an icon of Swiss horology, famous for its extreme shock resistance and the distinctive embossed turtle on the case back. Technical Specifications: Brand: Certina Model: DS "Turtle Back" (First Generation) Reference: 346.825 Serial Number: 5201018 (Inside case back) Movement: In-house manual winding Certina Calibre 25-66, 17 Jewels. Case Material: Stainless Steel. Case Diameter: 36 mm (excluding crown). Dial: Original silver/champagne dial with a beautiful, uniform vintage patina. Applied steel markers and original dauphine hands. Crystal: Original Acrylic (Plexiglass). Strap: New orange vintage-style leather strap (250mm total length). Condition Report: Movement: Very clean and in excellent working order. The iconic yellow rubber shock-absorber ring is present and in great visual condition, which is rare for this age. Case: Good vintage condition with honest signs of wear, maintaining its original sharp edges. The "Turtle" logo on the back is clearly visible. Dial: 100% original, showing a natural ageing process (patina) that adds to its authentic vintage character. Shipping: The watch will be carefully packed and shipped from Germany via DHL Express with full insurance and tracking number.