The Brass Duet Incredibell
is one of the best bicycle bell out there. It's got the "beautifully resonant
ring of solid brass" and a striker that will not ring the bell no mater how many potholes you're riding over. Unfortunately the clamp will only fit handlebars with 21.7mm - 24mm (.86" - .95") outside diameters. I present to you a way to modify your bell to fit any handle bar width. Here the hacked bell is mounted upside down (just my preference, I like ringing with my right thumb, don't worry, rain will not get in the bell).
In addition to the bell, you will need a utility knife, screwdriver and a large clamp from most any front light mounting kit (the large size is almost never used so you might be able to get one for free at your local friendly bike shop, or bike dude/dudette)