A pair of 1/72nd scale depth charge racks. These are 1 of the tall racks used by some of the Flower Class corvettes which can be made from the Revell kit.
The stern of the kit's hull will need to be modified to make these parts fit. This will mean filling the lower part of original openings in the stern bulwarks and cutting away the upper portion above the kit's opening.
The racks will also need depth charges for this product, a total of 18 are needed for a pair of racks. I have done a sprue of 4 here -
https://www.shapeways.com/product/6N6PDBCEA/depth-charge-x4?li=shop-results&optionId=15292909