The Betrayer Shackles are created by Selderin Vermth to imprison mages who intrude on his home.
As an action, you can throw the shackles in the direction of a creature (range 20 feet). The target must make a Dexterity saving throw (DC 14) or be shackled, causing the user from being unable to use any spells. On it's turn, the creature can make a Strength check to try and break three (DC20).
The shackles then lose this property until the next dawn.