Code point
U+29CB
Glyph appearance depends on your fonts.
U+29CB
SmU+29CB TRIANGLE WITH UNDERBAR is a Unicode 16.0.0 character in the Math Symbol category. It belongs to the Miscellaneous Mathematical Symbols-B block.
Choose the representation you need, then copy its value.
U+29CB
10699
⧋
⧋
E2 A7 8B
29CB
000029CB
%E2%A7%8B
\u29CB
\u29CB
\u29CB
\29CB