This lens mount adapter is for PRAKTICA B mount lenses on M4/3 mount cameras as long as your lens is PRAKTICA B mount and your camera is M4/3 mount. then it is useful. 

I can only speak for my Nikon 50mm f1.8 Ai-s manual focus lens and the Olympus Pen-E PL7. The K&F Concept® Nikon - M4/3 lens mount adapter ring for Nikon AI lens is well suited for this. The adapter sits firmly and without play on the lens and can be easily attached to the m4/3 bayonet. 

According to the K&F concept homepage, the surface treatment for this adapter is "anodized" and that means anodized. Anodised layers are used to improve the appearance and functionality of the surfaces of aluminum materials; With the adapter, the aspect of wear resistance (contact surface to the camera) should play an important role (a black lacquered connection surface would probably start to "dissolve" after a few adaptation processes).