They are available in a range of shapes so there is a scraper for flat surfaces and a scraper (gooseneck) for concave surfaces such as the inside of a bowl.
A carefully formed hook or burr is formed on a scraper that 'cuts' fine amounts of wood to produce a reasonably smooth surface. Often for a finer finish, an abrasive such as Abranet is required.
The burr of a scraper is formed by a Burnishing Tool.
Our Cabinet scrapers are made by British tool makers Thomas Flinn.