Xiaomi Mijia T301 Sonic Electric Toothbrush, IPX8 Waterproof, High Frequency Vibration, Wireless Charging, 50 Days Battery Life HIGH-FREQUENCY VIBRATION: 31000 times / per minute High-frequency vibration, Low noise technology, remove tooth stains more easily. RUST-FREE ANTIBACTERIAL BRUSH HEAD: The Mijia T301 Sonic Electric Toothbrush head uses copper-free implant technology, which does not produce metal rust stains and inhibits the growth of bacteria. The bristles are cut at an angle of 10° on the outside of the brush, and the tooth-shaped bristles are more gingival-friendly. LONG BATTERY LIFE: Mijia T301 Sonic Electric Toothbrush has 50 days battery life, it supports wireless charging, safe and portable. The toothbrush supports flash charging, you can brush your teeth just charge the Toothbrush in 2 minutes. IPX8 WATERPROOF: Mijia T301 Sonic Electric Toothbrush supports IPX8 waterproof, all-in-one body, double seal design.