Slave Ring

Book of Vile Darkness 3.5
By Monte Cook

This iron ring, once put on, cannot be removed except by the wearer of the master ring keyed to it. The wearer is subject to horrible, flesh-disrupting damage by the wearer of the master ring, and she can also exchange messages with him.

Caster Level: 7th; Prerequisites: Forge Ring; Market Price: 500 gp.