This is a New Old Stock/Never Ran Vintage COX Black Widow .049 No.150 two stroke model airplane engine.  The Black Widow was the most powerful reed valve .049 engine available when introduced and featured a Snap Starter System with a larger tank for longer flights. Includes the original box in very good condition, care/operation sheet, 2 color stickers for application on your model and 2 Cox Wrenches Part No. 21530.  Item has been part of current owner's collection for over 20yrs and stored in a pet and smoke free home.