A large vintage white enamel with black trim tray.  17" X 11 1/2".  There is minor chipping on the outer edge and surface wear on the bottom.  This is a heavy tray.  
 
Here is a link to an extensive history of enamelware:
Enamelware, vintage porcelain or enamel kitchenware, graniteware, agateware, speckleware, timeline (oldandinteresting.com)