The Lock Technology 12-pc Metric Shockit Line Wrench Set, No. LT1930, is designed to loosen fittings on steering, brake, AC, and fuel systems. It uses the force and vibration of an air hammer. With a compact design, its able to reach difficult line nuts with an offset punch. The LT1930 is built to precise ISO 1174-2 DIN tolerances and has indexed holes to keep Shockit Punches from slipping off line wrench. The set must be used with Shockit Punches (sold separately) for maximum performance and warranty coverage, the company says.