compass prover, brunton pocket transit, military lenstatic, chinese knock off

first i built a compass prover. then i tested the chinese pocket compass m2 and the brunton. since i used the lenstatic to find north, i tested a second time using the brunton to establish north. in both cases, the chinese pocket compass m2, was out by 1/2 degree. for the cost, i was amazed at how accurate it was. if you need a quality compass, and cant afford 600-700 for a brunton, this is a fantastic option. in my amazon review, i gave it 4 stars as the mirror is maybe a low quality plastic or low quality metal. don't touch it, it is almost impossible to clean. This note is added after posting. Anticipating that someone might balk at having a half a degree error from magnetic north to be a real issue, do keep in mind that this is not typically a back packing compass. While I have not worked on projects that take in the whole state of Alaska, i do not see that using this on property up to several acres to be an issue. The error is very slight unless you are talking miles. It could also be adjusted with the screw to turn the bezel if all bearings are magnetic. Compensating for true north is just adding or subtracting the declination at your location. It is not the end of the world to have a slight error. Most people have never proven their compass and do not know if the compass carried is accurate or not.