The Sageo is a cord made of silk or cotton, Normally it is a cord that either made of silk, rayon, cotton or leather, and going through the Kurigata of the Saya (scabbard) and  keep it from slipping, that keeps the sword in the belt. It is also used at times to secure the katana  into its saya by wrapping the sageo around the tsuka and tying it  off. It is easy to creat your custom sword by swapping out the  Sageo. Following Segeo are imported  from Japan, they are available to all who choose to upgrade the  appearance of their Saya. 

However, for formal occasions wearing a Sageo that matches the colors of one’s dojo is recommended especially for those who are into certain schools of martial art.