A mask for silicon crystallization capable of minimizing the number of grain boundaries in crystallized silicon, a method for crystallizing silicon using the mask, and a display device are presented. The vapor barrier is applied to, or forming an integral part thereof, an interior surface of an electrical cover plate and particularly useful for exterior electrical boxes prior to installation. The locking member engages the recess thereby preventing the connector’s removal from the appliance inlet when the connector is received therein, and disengageable from the recess thereby allowing the connector’s removal from the appliance inlet by forcing to the locking member in a direction inwardly of the connector. The chimeric ErB heteromultimer adhesins of the present invention are useful as competitive antagonists or agonists of a neuregulin for the treatment of diseases such as various cancers.