Tangle Teezer was the hairbrush brand invented by Shaun Pulfrey and rejected by all the Dragons on Dragon's Den.
Pulfrey developed the brush after noticing how difficult it was to remove tangles without pulling or damaging hair. He presented the invention on the British programme, but the Dragons did not invest. Pulfrey nevertheless continued developing and marketing the product, which later became a widely recognised detangling brush brand.
The programme appearance is often remembered because the pitch ended without a deal despite the product's later commercial success. Tangle Teezer is a brand name, not a generic description of every detangling brush. WetBrush, Mason Pearson and Denman are real hairbrush brands, but they are separate companies and products. The episode illustrates that a television investment decision captures the panel's assessment at one moment and does not determine whether a product can eventually find customers or build a successful business.