The Up Down Double Arrow symbol (⇕). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Arrows.
The quickest way is to copy ⇕ from this page and paste it anywhere. You can also insert it with its Unicode, HTML, or alt code listed above.
⇕ is U+21D5 (decimal 8661).
Use ⇕ in HTML to render ⇕ on a web page.
On Windows you can type it with Alt+8661 (hold Alt and enter the number on the numeric keypad).
Yes — copying is completely free and unlimited, and works right in your browser with no sign-up.