1. COMPATIBILITY: Our replacement brush heads are compatible with all Lächen electric toothbrush models (RMT5B, RMT8B, RMH9, RM051B, RMT7, RMST031) and Olybo toothbrushes. 2. 3D CURVING DESIGN: Each brush head features an ergonomic 3D curvature design that adapts to the natural contours of your teeth. The curved bristles penetrate deep into the interdental spaces and gum line to effectively remove plaque and allow for comprehensive mouth cleaning. 3. COMFORTABLE BRUSHING EXPERIENCE: Our brush head is made of mediumsoft American DuPont bristles that gently protect the gums while efficiently cleaning the teeth, providing a comfortable brushing experience for daily use. 4. MATERIALS: The brush heads are made of durable ABS and TPR materials with DuPont nylon bristles to ensure longlasting performance and oral hygiene. They are easy to install and in seconds.