Within 18 months, your Braun shaver will cut an average of 6,000,000 hairs. In accomplishing this substantial task, the cutting parts will gradually wear out and your shave may become less close and comfortable. Thats why Braun recommends changing your shavers foil & cutter block every 18 months to maintain your shavers maximum performance. For an efficient shave every day. Includes: Braun Shaver Replacement Part 52B Black. 1ml. Get back 100% performance on your Braun shaver for a fraction of the original cost. Compatible with old and new generation Series 5 (5040s, 5030s, 5020s). Easily replace your Braun shaver parts every 18 months to maintain peak performance. Small investment, peak performance. Compatible with Series 5 shavers.