Braun 73s shaving cassette (silver) for shaver models listed below. Within 18 months of daily use, your Braun shaver cuts an average of 6,000,000 hairs. During this time the cutting parts will gradually wear out and you will notice a reduction in performance and comfort. To maintain the high performance level of your Braun shaver, the shaving head should be replaced within 18 months. Fits Type 5764 shavers only.