sentences:  Nose rings specifically designed for pigs usually consist of open copper or steel wire rings with sharp ends, about one inch (about 2.5 cm) in diameter.These are typically clipped to the rim of the nose instead of through the septum, as this is far more painful to the pig and is considered "thus more effective for deterring the pig from rooting than piercing through the septum is".As they may sometimes become dislodged, an adult pig may be given three to four rings.