You'll wonder how you ever straightened your hair without it. Convenient built-in brush with nylon and boar bristles makes comb-out super smooth. Metal chambers help retain heat, for a fast, professional style straightening. Use the straightening brush alongside your hair dryer (using the vented head), for super straight hair every time. Bristles, nylon and boar. Metal, plastic. 9 1/4" L x 1 5/8" W.