Ferrules

Ferrule is a small deformable metal tube, generally made out of tin plated copper. This short tube (or long ring) is placed over a section of stranded wire extending from stripped insulation, then compressed with a crimping tool to hold the strands together. Once crimped, the bundle is transformed into what, for practical purposes, acts as the end of a solid-core wire. Electrical insulation may be included to protect any exposed portion of the wire not completely inside the screw terminal post.