Code point
U+21CB
Glyph appearance depends on your fonts.
U+21CB
SoU+21CB LEFTWARDS HARPOON OVER RIGHTWARDS HARPOON is a Unicode 16.0.0 character in the Other Symbol category. It belongs to the Arrows block.
Choose the representation you need, then copy its value.
U+21CB
8651
⇋
⇋
⇋
E2 87 8B
21CB
000021CB
%E2%87%8B
\u21CB
\u21CB
\u21CB
\21CB