The Box Drawings Double Vertical and Left symbol (╣). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Box Drawing.
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+2563 (decimal 9571).
Use ╣ in HTML to render ╣ on a web page.
On Windows you can type it with Alt+9571 (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.