On the vintage Astronaut the time was set by a recessed key on the case back which would be flipped up and twisted leaving
link no trace of a crown on the watch's profile from any angle. Here Accutron recessed the crown into the side of the case so it tucks under the bezel to keep the aesthetic when viewed from the front and
link the half sapphire case back mimics the shape of that original key while leaving space for the engravings for which of the
link 300 watches you have.