This pocket compass is 1.5" in diameter with a hinged lid and made of brass. The compass has a locking mechanism to lock the needle in place when not in use. There is a button on the side of the compass that you slide to lock or unlock the needle. It also has a ring on the lid to attach a leather lace for wearing around your neck or to prevent your compass from being lost when attached to your shooting bag or haversack. One compass similar in style was found in Albany ,New York at an archaeological dig several years ago. I am not saying this is an exact copy , but something close in style of what was found. The compass works well ,but you need a steady hand when reading the compass as the needle is sensitive to movement. Other than that it is a great inexpensive compass to use for reenactments or your next trip into the woods.