Thank you for viewing. This hairbrush is designed for those with thinning hair or hair that has become weak, and is gentle on both the hair and scalp. The natural oils contained in the natural wood "Zelkova" blend with the scalp's oils, and the more you use it, the more natural shine and suppleness it will give your hair. Material: Zelkova + Natural Rubber (Base) Length: 24.6cm Width: 9.8cm Round hairbrush. Included: 1 storage bag, instruction manual. Air hole: 1; There is one air hole to maintain the balance of air pressure between the inside and outside of the hairbrush. It looks like a pin has come out, but it is not a defect. #AzunyanStore