Zischägge, Ottoman workmanship

The lobster-tailed pot helmet, also known as a zischägge, is a conical helmet mounted on a spherical or pear-shaped block and originated in the Ottoman Empire in the earlier half of the 16th century.
The model seen here is amongst the more reserved, created by the workshops in the city of Constantinople (now known as Istanbul). There is gilding or engraving to embellish the polished surface of the head protection, but only in the form of fine vertical grooves, which start at the skull and rise up to the crest block.
A band of rivets passes along the lower edge of this head protector, doubtlessly used by the combatant to attach chainmail and also to provide increased protection for the neck and face.