A manufactured fibre containing at least 85% by weight of a long chain polymer of vinylidene dinitrile (-CH2-C(CN)2-) and having the vinylidene dinitrile group in no less than every other unit in the polymer chain (FTC definition). Nytril fibres have a low softening point so they are most commonly used in articles that do not require pressing such as sweaters and pile fabrics. They are also blended with wool to improve shrink resistance and shape retention.