UNK Guitars was a brand owned by Paul “UNK” Unkert of Toms River, NJ. Paul Unkert had previously worked for Kramer and in 1979 made two guitars for Eddie van Halen. UNK guitars were made in the USA but there was also a more affordable version made elsewhere under the XMark brand name. The brand was active from around 2008 to 2012.

Source: UNK Guitars website (archived 2012)