Clinking. The Guard has disadvantage on Stealth checks due the the chained nature of thier armour.   Manacles. The Guard is equipped with manacles, when they have a humanoid grappled. They can can use thier action to try to bind them. To do so, they make another grapple check. If they succeed, the target is both incapacitated and restrained until the grapple ends, and will remain incapacitated until the manacles are removed by another creature.