A hairbrush that is gentle on both the hair and scalp, made for people who have thinned or thinned hair. Material: Tree of Load Length: 25cm Width: 8.5cm [One year warranty] This product comes with a 12 month warranty for the manufacturer. Air hole: 1 piece; There is one air hole to maintain the balance of air pressure inside and outside the hairbrush. It is the size that the pin has come off, but it is not a defective product. The tipless pin, made of a material that does not easily generate static electricity, is effective for massage with a pleasant stimulus without damaging the scalp. Not only can you make your hair look better, but you can also improve thinning hair, relieve stress, moderately stimulate your scalp and massage.