Threaded inserts is looks like spring and often used in low strength and think materials or objects such as casting iron, AL, MG and etc elements.Helical coil could improve the joint strength and anti-abrasive, at the same time, it could improve the thrust surface, flexible coupling and clear up the tolerances between the pitches and half of thread angles of the inside & outside threads. 5 per pack, about0.5 kg, 10*10*10.
