I thought this is nothing more than a joke. I mean, why would anybody save half a banana? Putting it in a different way, who would not finish a banana? Apparently, a lot of people do.
There is a saying in Economics that demand determines the supply. Here it goes, a NANA SaverTM.
The product description goes, Keeps a sliced banana fresher, longer by reducing exposure to air. Hinged banana shaped body with tiny teeth grip sliced bananas firmly in place and flat plate presses snug against banana face to minimize air contact. Top-rack dishwasher safe. Plastic.