These great magnets are coated with a durable layer of plastic. The 1" x 1/2" x 1/4" dimensions are the finished dimensions of the plastic coating. These blocks can be slammed together many times without damage. They won't mark or scratch surfaces they come in contact with. They are also completely waterproof and weatherproof. Please note: Slight color variation may occur from order to order.
NOTE: As of June 2014, these magnets have improved! With a textured, more consistent plastic surface, these magnets are nicer to handle. The surface also helps increase friction a bit more than a completely smooth surface.