The watch in the image is a Dubey & Schaldenbrand Index Mobile, a split-seconds chronograph that is practically brand-new and comes from our inventory. This model is known for its unique "single-split-seconds" mechanism, invented by founder René Schaldenbrand, which uses a visible spiral spring between the second hands to enable the split-seconds function more simply than traditional systems. Model Details: Movement: Generally based on the Landeron 248 manual-winding caliber, modified with the Index Mobile module. Dial Features: Features two sub-dials, Arabic numerals, a telemeter scale (in red), and a tachymeter scale (in blue). Case: Usually made of gold-plated stainless steel (gold plaqué) with a diameter of approximately 37.5–38 mm excluding the crown, 47 mm between the lugs, and 14 mm thick. Operation: Pressing and holding the button on the crown stops the upper seconds hand while the lower one continues to run; releasing the button causes the hands to overlap again. Comes with a vintage leather strap and generic buckle. All our watches are serviced before being put up for sale to ensure your new timepiece functions properly. For further information, please do not hesitate to contact us and we will respond as soon as possible. Thank you.