The Box Drawings Down Double and Right Single 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+2553 (decimal 9555).
Use ╓ in HTML to render ╓ on a web page.
On Windows you can type it with Alt+9555 (hold Alt and enter the number on the numeric keypad).
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