Kelvin Sign
HTML Entity Browser Test:

U+212A is the Unicode hex value of the character Kelvin Sign, which is categorized as "uppercase letter" in the Unicode 6.0 character table.

"Kelvin Sign" was previously named "DEGREES KELVIN" in older versions of Unicode. In addition, U+212A is a composite character comprising of one or more other Unicode characters modified or combined.

Unicode Character Information
Unicode Hex U+212A
Character Name KELVIN SIGN
General Category Uppercase Letter [Code: Lu]
Canonical Combining Class 0
Bidirectional Category L
Decomposition Mapping 004B
Mirrored N
Lowercase Version U+006B
Unicode Character Encodings
Kelvin Sign HTML Entity K (decimal entity), K (hex entity)
Windows Key Code Alt 8490 or Alt +212A1
Programming Source Code Encodings Python hex: u"\u212A", Hex for C++ and Java: "\u212A"
UTF-8 Hexadecimal Encoding 0xE284AA
1 To type a Unicode symbol in Windows, hold down the ALT key and enter the decimal or hexadecimal code provided using the numeric keypad. The decimal alt code (Alt 8490) will only work on computers with support for this Unicode character in the active code page. The hexadecimal alt code (Alt +212A) will work for all Unicode characters provided Hex input from the numeric keypad is enabled.
* If the Kelvin Sign character does not display correctly in your browser, you may not have a Unicode font on your system that supports this particular symbol.