The forehead protector is the headband that is worn by almost every ninja, composed of a metal plate engraved with the symbol of the ninja's Hidden Village, and normally a band of cloth which can be in different colours. The forehead protector is received once a ninja graduates from the Academy,and genin-level or higher ranked ninja are the only ones allowed to have and use them.

Despite the name "forehead protector", it can be worn in many different styles. 
Head Band