A sifter is a kitchen tool used to separate and break up clumps in dry ingredients such as flour, sugar, and cocoa powder. It typically consists of a mesh screen or fine mesh that allows smaller particles to pass through while retaining larger ones. This process helps to aerate the ingredients, making them lighter and easier to mix. Sifters come in various designs, including hand-held models and those that can be operated with a crank. They are often used in baking to ensure a smooth texture in recipes, contributing to the quality of baked goods like cakes and pastries.