Sorry for the typo. I meant to say 0.1 degree. I just went out to the shop and looked at it again to be sure. It only reads to a tenth of a degree. It also has arrows to show which side of zero that the reading is and I hadn't mentioned them before.
There are 3 button magnets imbedded in the bottom to attach it to steel surfaces. The unit comes with the battery and it is a standard CR2012 button cell that's readily available. It is accessed through a round 1/4 turn twist-off type back door. The front and back of the unit are plastic but the sides, top, and bottom are a one piece aluminum extrusion. It is about 2 inches square and 1 1/4 inches thick. There is an on/off button and a zeroing button on the front and those are the only controls that it has, so it is very simple to use. Whatever you place it on becomes zero degrees when you press the zero button. Then you place it on a second surface and it displays the angular offset with respect to the surface that you had zeroed it to. Both surfaces can be angles with respect to true level. It compares one to the other and shows the degree offset to the nearest tenth of a degree.
Barry Wixey sells other digital displays, but rather than try to list them you can go to his website and see for yourself. He's providing free shipping if you order from his website.
At the time that I ordered mine he was out of stock, but I was notified immediately when it would be shipped (3 day delay) and it arrived a day sooner than he had said that it would. Many small companies don't even check their websites for orders for several days at a time let alone ship that quickly.
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have no connection to Wixey or his website. I'm just a satisfied customer.