Personal Defense Brush Black. This brush is the perfect concealed self-defense tool on the planet. These are covert, disguised in a brush these knives are perfect for protection in nightclubs and even on the street. A harmless hair care accessory at first sight, this fully functional brush transforms into a knife, but not just any knife. By taking the brush apart, you reveal a 4.25 inch blade made from strong ABS plastic that can deal a great amount of damage to any attacker. Product Features Plastic Brush Knife complete with window breaker/skull crusher Legal to carry inside of clubs and on the street Made from Hard ABS plastic Super sharp 6.25 Inches overall length