Thick & Curly- Two-Tiered Stronger Teeth- Palm-Friendly Size- Patented Two-Tiered Teeth Technology in Firm-Flex GROUND-BREAKING TECHNOLOGY. Our patented two-tiered firm-flex teeth have been adapted for thick and curly hair. The long, soft teeth detangle, removing knots and reducing breakage, while the short teeth smooth, for glossy, frizz-free hair