Specifications: How to Use Watermelon Slicer Cutter Knife? Step One:Confirm the size (0-2 CM) of watermelon cube you want to cut. Step Two:Hold the watermelon by hand. Just push our watermelon slicer tool into watermelon. The Windmill slicer blade will cut watermelon into cube automatically. Step Three:Extract the slicer out. Perfect watermelon cubes come out. Step Four:Put the watermelon cubes on the dish. Enjoy it.