An aventail or camail is a flexible curtain of mail

Mail (armour)

Mail is a type of armour consisting of small metal rings linked together in a pattern to form a mesh.-History:Mail was a highly successful type of armour and was used by nearly every metalworking culture....

 on a helmet

Helmet

A helmet is a form of protective gear worn on the head to protect it from injuries.Ceremonial or symbolic helmets without protective function are sometimes used. The oldest known use of helmets was by Assyrian soldiers in 900BC, who wore thick leather or bronze helmets to protect the head from...

 that extends to cover the neck and shoulders. The mail could be attached to the helm by threading a leather cord through brass

Brass

Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...

 rings at the edge of the helm. Aventails were most commonly seen on bascinet

Bascinet

The bascinet was a Medieval European open-faced military helmet, typically fitted with an aventail and hinged visor. The term is also written as bassinet or basinet.-Early versions:...

s in the 14th century and served as a replacement for a mail coif

Coif

A coif is a close fitting cap that covers the top, back, and sides of the head.- History :Coifs were worn by all classes in England and Scotland from the Middle Ages to the early seventeenth century .Tudor and earlier coifs are usually made of unadorned white linen and tied under...

. Some aventails were decorated with edging in brass

Brass

Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...

 or bronze

Bronze

Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

 links (sometimes gilded), or with a zig-zag lower edge (vandyked). By the late 15th century, the aventail had replaced the mail coif completely. Only those who were poor or who were collectors of the sort had a mail coif.

Aventails were typically attached to the helmet via small staples known as vervelles

Vervelles

Vervelles are small metal staples used in Medieval armour to attach an aventail to a helmet. A leather cord would be woven through the top row of rings and the vervelles, securing the two together....

.