The Planisphere Watch will show you the constellations visible in the Northern Hemisphere (between 35 & 50 degrees latitude). Just turn the bezel so the current time is aligned with the date to determine which major constellations are visible. The watch features a 43mm diameter brass case and crystal dome lens with a rubber band that has stainless steel links.
It has quartz movement and a “super luminescent” dial that illuminates the star chart for 2-3 hours without batteries. It is a guaranteed nerd conversation starter, but the watch face is small, so it’s only going to to show a handful of constellations.