Spyderco Butterfly Knives are pretty cool flippers. These butterfly knives infuse traditional Balisong elements with innovative Spyderco features. Balis are all about swinging, sometimes called doing the dance. Notice that these knives incorporate Spydercos Trademark Round Hole into both handles. The holes position the thumb and fingers (pinching either side of the handle) for superb control while indexing/rotating and enhancing fluidity of the swing.