C.H. Hanson Precision Ball Level
Instead of a tiny inscrutable bubble, this tool uses a two-inch-wide ball so you can quickly determine level and plumb without squinting. Modeled after a cockpit's horizon indicator, the ball sits in a mineral-oil-like fluid and indicates the pitch and angle of the slope. A brass weight inside keeps the ball anchored toward the earth as it rotates 360 degrees, so the level can check two directions when laid on its back, perfect for setting tile.