31.20 mm x 3.97 mm (height) x 1.50 mm thick round domed sapphire crystal with a cut out at the 3 o'clock position, generic (not genuine), fits Cartier® Ballon Bleu. Using generic crystals may devalue your watch.
* H. & W. Perrin Company Limited is independent of and not affiliated with or sponsored by Cartier®. Cartier® warranty does not apply to parts supplied by H. & W. Perrin Company Limited.