Vintage New Old Stock Sprague Vitaman Q 0.47 microfarad 300 volt paper in metal capacitor.  RCA Service Parts box.  Sprague part number 81P47493S15, RCA part number 207136.  About 0.56 inches diameter, 2.15 inches long.  Tests good.

Shipping can be combined with other parts, equipment, and vacuum tubes in my Ebay store.  Add to cart and pay together.