Negative ions replenish water moisturize hair & no longer frizz. Natural mane enhance hair gloss. Sonic vibration easy to comb & develop knots without trouble. Gauss magnetism scalp comb pressure to achieve deep comfort. Exclusive steel needle design antibacterial & anti-sebum oxidation. Extremely convenient USB (Universal Serial Bus) charging easy to carry when going out. Exclusive ergonomic design easy to hold comb & save effort. (include battery no warranty)