Starrett’s 135-series pocket levels feature a hexagonal body with curved ends and a satin nickel-plated finish. They’re available in two lengths, 2-1/2″ and 3-1/2″, with both versions featuring a single clear bubble vial.
These look to be great for machine-shop use, and other applications where an ordinary 9″ mini torpedo level might be too large or awkward to use.
There’s also the potential to stow one way in a portable tool kit for on-the-go leveling use. Even though there are plenty of iphone and Android bubble level apps available, I have never used any of these applications in any real capacity.
You can find these levels (135A, 135B) at your favorite industrial suppliers for about $23-25 each.
If you need a relatively compact pocket-friendly level, but don’t need the precision or durability these Starrett levels provide (or the cost that comes with all that), you could always pick up a simple bullseye level for cheap.