Pocket Sensitive Hair Bursh SB4. Created with five rings of tufts for a smaller, but just as effective brushing experience, a Pocket Sensitive Bristle is your perfect travel companion that can easily be packed into your handbag, laptop bag or even a childs change bag. Often used for very fine or thinning hair, people who are losing their hair for medical reasons, including alopecia and chemotherapy, sensitive scalps.