This is a very interesting antique knife, charm or pendant. It is made in Western Germany. I am unable to discern the makers mark but it could possibly be MB. It has some damage. In particular the siding on both sides is cracked and chipped. Either way, it is a very interesting piece and would make a great addition to a collection. It weighs approximately 7.4 g. In the closed position it measures approximately 1.5 in with the blade retracted it measures 2 1/8".  1/4" thick. Please message me if you have any questions. Thanks for looking