For $4.99, this thing works great! Very easy to view.
Magnetic base sticks to the metal roof, and I put it on my flat metal dash when I move the bus, to level it. 1/4 turn shows me level right & left and 1/4 turn shows me level front to back.
If I'm leveling outside bus, it sticks to metal sides and bumper.
I noticed if my air bags are inflated, it shows 6° out of level... Dump the bags and it goes level.
I installed a tv mount swivel pole from floor to ceiling with 1 1/2" conduit, and the angle finder showed me I needed to make a 15° cut for the top... Fit perfectly!
I keep it stuck to side of refrigerator.