A chime of opening is a hollow mithral tube about 1-ft long.

When it is struck it sends forth magical vibrations which cause locks to open. Likewise lids, doors, valves, and portals will open when the chime is sounded. The device will function against normal bars, shackles, chains, bolts, etc. It also destroys the magic of a hold portal spell or even a wizard lock cast by a magic-user of less than 15th level. 

The chime must be pointed at the area of the item or gate which is to be loosed or opened. 

It is then struck, a clear chiming ring sounds (which may attract monsters), and in 1 round, 1 of the functions of the device will be completed, i.e., a lock opened, a shackle loosed, a secret door opened, the lid of a chest lifted, etc.

Note that if a chest is chained, padlocked, locked, and wizard locked, it will take 4 or 5 soundings of the chime of opening to get it open. 

A silence spell negates the power of the device.

The chime has 20-80 (10 + d6 x 10) charges before it will crack and become useless.