Is it real or is it Bummerex?
Hard to tell! But the copy that came with it is interesting!
"Trefethen- a varient of the Cornish name Trevethen, ... Trevathen and Trevethan.... from the placename Trevathan, in St. Eval, Budock or Gwennap. ... Trevethan... meaning "homestead in a meadow".
Source: Donald Perry Trefethen, 1992