The bracelet is available only for Panerai Luminor watches in a variety of materials and finishes according to the watch. It is integrated with the case and therefore not interchangeable with a leather strap for Luminor watches with a 44 mm diameter case, while 40 mm Luminor watches can also be fitted with a leather strap.
Source http://www.panerai.com/s_page.xpd?id_lingu..._tipologia=3651