Check boxes are similar to radio buttons, except that they can offer multiple-choice selection as well as individual choice. Check boxes offer the user a fixed list of choices, with the option of selecting more than one, or even all.

Check boxes also toggle application features on or off. For example, a word processing application might use a check box to let the user turn word wrapping on or off. A check-box control sends WM_CONTROL messages to its owner window.