SRD:Chime of Interruption

Chime of Interruption: This instrument can be struck once every 10 minutes, and its resonant tone lasts for 3 full minutes.

While the chime is resonating, no spell requiring a verbal component can be cast within a 30-foot radius of it unless the caster can make a Concentration check (DC 15 + the spell’s level).

Moderate evocation; CL 7th; Craft Wondrous Item, shout; Price 16,800 gp;Weight 1 lb.