Code point
U+339F
Glyph appearance depends on your fonts.
U+339F
So<square> 006D 006D 00B2U+339F SQUARE MM SQUARED is a Unicode 16.0.0 character in the Other Symbol category. It belongs to the CJK Compatibility block.
Choose the representation you need, then copy its value.
U+339F
13215
㎟
㎟
E3 8E 9F
339F
0000339F
%E3%8E%9F
\u339F
\u339F
\u339F
\339F