Empire Level EM81.9G 9 Inch Magnetic Torpedo Level w/Overhead Viewing Slot (Made in USA) OVERHEAD VIEWING SLOT built into the top of this level lets you see what youre doing even when looking from above MAGNETIC EDGE lets you mount this on metal or on piping, keeping it hands-free if you need to work with other tools PIPE GROOVE built into the edges allow you to slide this neatly underneath or on top of piping so you can get more accurate measurements HIGH CONTRAST VIAL SURROUNDING: Bright white circles surround the leveling vials. This helps you see the liquid on most surfaces READS: Plumb, level, and 45 degrees