This set of 2 stainless steel watch spring bars will fit Calibre de Cartier 42mm watches with model numbers 3299, 3301, 3366, 3389, 3576 and 3578. These bars are used to attach the strap to the watch case.
These were not made by Cartier but are high quality compatible parts made to fit Calibre de Cartier 42mm models.
Second image shows where to find the strap code (KD3JJL04) stamped on the underside of your watch strap.
If you are not sure if this will fit your watch or if you have any other questions, feel free to email me at Sales@TheWatchLink.co.uk. I'm happy to help!