quality: Equipped with a cutting edge dual blade system with lift and cut technology. Stainless steel blades provide a comfortable close shave. Suitable for meticulous grooming and safe use. The flexible pivoting head adapts to any surface, delivering performance. Compatible models: Blade model 21B, compatible with all electric shavers series 3 shavers 301S, 310S, 320S, 330S, 340S, 360S, 3000S, 3010S, 3020S, 3030S, 3040S, 350CC, 370CC, 3050CC, Cruzer 6 and so on. Professional shaving head: 21B shaving head with floating lock, precision tooth comb technology and bionic mesh design fits your skin and grips the male hairs firmly, thus removing them easily without damaging the layer of skin. Bring you a more comfortable and efficient shaving experience. Long lasting: The lifespan of the foil and cutter replacement heads compatible with the S3 varies with daily use. For performance, every 912 months. This ensures that you always enjoy the haircutting experience. Replacement foil heads are easy to install and remove. Clean the shaver before installing the foil. Use scenarios: Daily grooming at home for precise beard shaping and a clean finish. Shaving around the jawline and neck where contours require a flexible head. Travel or on the go maintenance with easy replacement and quick installation for reliable performance.