On the BBC television show Dragon's Den, Tom Pellereau's filing product was called Stylfile.
Stylfile is a range of curved nail files designed to follow the shape of a fingernail. Pellereau presented the idea on Dragon's Den and secured investment from Lord Alan Sugar, making the product one of the show's notable invention-led pitches.
The product name is sometimes mistaken for a description of the filing technique, but Stylfile is the brand name. Pellereau's pitch is also associated with the show's format because the investment followed a live demonstration of a simple consumer product rather than a complicated technology proposal.
Pellereau later became known for developing additional consumer products. His Dragon's Den appearance is distinct from the programme's better-known food and retail deals, so the answer depends on identifying the specific filing invention rather than naming an investor or a later product.