Notice: this is not a compass - Brunton Omnislope Aluminum Compass

This is an inclinometer, it measures slopes. Do not buy this if you need a compass. The product description is terrible and should be edited by a knowledgeable person not a product bot. I'm giving this a one star rating because the product is not described well. I have not used this particular instrument, but I have used this style of inclinometer and the picture looks like it would perform well to measure vertical angles. Look at Brunton's web site to get a better idea of what this instrument does.