Chris Reeve Tanto Umnumzaan Knife Titanium Folder Plain Edge Right Handed Folder. Typical of Chris Reeve Knives, the pivot strength is more robust than other folders. The large pivot screw and pin are supported by large thrust washers. These perforated phosphor bronze washers reduce friction and double to retain the fluorinated grease for longer lubrication thereby extending the life of the knife. A ceramic ball creates the interface between the blade locking surface and the integral locking arm surface. The ball doubles to drop into a detent on the blade to ensure the blade does not open accidentally.