Bahco ERGO(tm) Oval Shaped Handle for Flat Half-Round Files. Developed according to the scientific ERGO(tm) process, to reduce muscle tension and the risk of injury. The hard polypropylene core, covered with a thermoplastic elastomer, provides a comfortable non-slip grip, and the handles smooth contours fit into the hand naturally. As a safety feature, the handle covers the tang and shoulder completely to prevent the hand from slipping off the handle onto the file blade.