The Double Superset symbol (⋑). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Math.
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+22D1 (decimal 8913).
Use ⋑ in HTML to render ⋑ on a web page.
On Windows you can type it with Alt+8913 (hold Alt and enter the number on the numeric keypad).
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