This is a very good combination baseplate/mirrored sighting compass. It could even be used for surveying, although for professional surveying I would prefer a GEO Transit with its locking needle and better sighting. However, the Eclipse Pro handles most situations very well, and with the sighting lines and some practice you will be able to produce very consistent and repeatable field readings. The compass includes some very handy reference cards with instructions on forward and reverse sighting, triangulation, map scales, a 7.5-minute quadrangle UTM grid, and other navigation techniques. The hinges are a little loose and spongy, so that the compass cover may want to close on its own a little more than it should (at 45 degrees I usually have to hold the sight cover in place with my finger just to see both sighting lines and the sight hole). It also includes a mirrored sighting clinometer, pretty accurate, and a hinge clinometer, which, to me, seems extremely inaccurate, especially given the loose hinges (the hinge index line has a mind of its own and is pulled maybe 5 degrees in either direction just by opening and closing the hinge). For some reason, the bubble level is not visible in sighting mode. I had to drill a hole through the plastic to make it visible, which would work a little better if the mirror were wider like in the GEO transits. Also, it is difficult to *accurately* align the needle disk Northing circle with the orienting circle, since the diameters are slightly different and the vertical space between them can easily lead to a one-degree margin of error just by the angle of your eye. You must be very vigilant to double-check yourself, a balancing act that takes some practice. However, the magnifying window works very well for taking easy-to-read azimuths, both forward and reverse. The needle disks are not global needles like on some other compasses, meaning that this compass is only good in one quadrant of the world, which is fine for me. The lanyard/reference card/rubber boot system is a little awkward, and I worry about creasing the cards with time. However, despite a few quirks, when it comes down to choosing a compass for near-professional surveying accuracy with both baseplate and sighting features, I would recommend none other.