Trinity College Concertinas are handcrafted instruments and authentic reproductions of the instruments introduced in the early 19th century in England and Germany. Trinity College offers both of the two major types-the Anglo and the English models. The Anglo model is a "bisonoric" design-much like today's harmonica-where a different note is produced by the "push" and "pull" motion of the bellows. This type of mechanism lends itself perfectly for many styles of ethnic or "folk" dance music. In this style, the straps cover the entire hand.