50 METAL INDUSTRIAL CLOSURES AND MOLDED PLASTIC INDUSTRIAL CLOSURES, BOTH COMPRISING PLUGS AND CAPS WHICH MAY BE APPLIED TO THE PROJECTING ENDS OF PIPE AND TUBING ASSOCIATED WITH MACHINERY OR APPARATUS TO PROTECT THE ENDS OF SUCH PIPE OR TUBING DURING SHIPMENT OF THE MACHINERY OR APPARATUS AND UNTIL THE SAME IS ULTIMATELY INSTALLED FOR USE