My daughter's 'Jumbo' zig zag is 7"x10", which was given to her as a gift from a friend who purchased it here at PM.
Kind of a round about way to give you the dimensions...
Plus, I've seen them even larger (8 1/2" x 11").
However, if you need the exact, laser ranged measurements, use Live Chat or send PM an email directly. They'll generally answer that request much quicker than they'll answer here ;-)