HEAD WARMER OR KNIT CAP
A knit cap, originally of wool (though now often of synthetic fibers) is designed to provide warmth in cold weather. Typically, the knit cap is of simple, tapering constructions, though many variants exist.
Historically, the wool knit cap was an extremely common form of headgear for seamen, fishers, hunters and others spending their working day outdoors from the 18th century and forward, and is still commonly used for this purpose in Scandinavia and other cold regions of the world. Being found all over the world where climate demands a warm hat, the knit cap can be found under a multitude of local names.