An emery board is an example of what type of file?

An emery board is classified as an abrasive file because it is designed to smooth and shape nails using a rough surface that effectively removes material. The surface of an emery board is covered with a layer of abrasive particles that help file down the nails, making it an ideal tool for nail care in both manicures and pedicures.

Abrasive files are known for their effectiveness in shaping and smoothing surfaces due to their gritty texture, which is specifically engineered to wear down harder materials like nails. This characteristic sets abrasive files apart from other types, which may not have the same level of effectiveness for this purpose.