The Benchmade BM42S Balisong Knife Titanium Butterfly Knife Spring-Latch Plain knife elements with innovative Benchmade features. Balis are all about swinging, sometimes called doing the dance. The Benchmade 42 series with the Weehawk blade. The handles are titanium and feature skeletonized channel construction. This 42 also has a spring latch to secure the knife open and closed.