Profile: W T I Fasteners Ltd. specializes in producing helical inserts for a wide range of applications. Our products include inserts, thread repair kits, wire insert taps, inserting tools, power inserting tools, tang break punches, extractors and gauges. The plain mandrel prewind tool is the most commonly used wire insert installation tool. Suitable for both free running and screw locking types of any manufacture, it is better suited to coarse pitch inserts.