PFSRD:Master's Perfect Golden Bell
From D&D Wiki
|This material is published under the OGL|
Price 20,000 gp; Aura strong abjuration; CL 15th; Weight 10 lbs.
This lustrous golden bell produces a deep and resonant ring which vibrates in perfect harmony with the Material Plane and destructively interferes with otherworldly beings. These vibrations reduce the damage reduction and spell resistance of all extraplanar creatures within 30 feet by 5 (for example, changing DR 10/magic to DR 5/magic). The bell has no clapper; to ring it, the bearer must attack it with an unarmed strike (this counts as an attack, with no attack roll needed, and does not damage the bell). The ringing lasts 1d6 rounds; stifling the ringing early is a standard action. It can ring for a maximum of 10 rounds per day.
Cost 10,000 gp