The name given to him refers to his monogram, which is a W followed by a key symbol.
Eighty-two works signed with that monogram are extant.
Many of these are ornament prints, depicting elements of gothic architecture and decorative objects, and were probably marketed mainly as patterns for other craftsmen to follow.
He influenced several other contemporary Dutch engravers, most notably Master I. A. M.
He probably worked for Duke Charles the Bold of Burgundy, and his ship series may have been "portraits" of the ducal fleet.