Twist end of the sanding brush pen to reach the desired length of bristles and stiffness as need.Advance and retract the bristles by turn end of the brush The scratch pen set includes 3 scratch brush pen in different materials, meet the cleaning and sanding needs of various scenario The scratch brush pen can be apply in many applications, the pen brush is good for tight place, electronic applications, rust The cleaning pen is insulated, feeling safe to cleaning your battery operated devices The fiberglass brushes are soft, good to cleaning your jewelry, watch and coin, Manufacturer: Bottone