The Mike Johnston Signature Groove Bell from Meinl is an innovative cowbell designed to give you more control over your sound. This cowbell has an excellent tone, and a middle-of-the-road sound that can work well for many different styles. To add to this, though, Meinl has also included two magnetic dampeners to give you further control.
The first is a small magnet that lets you control the overtones of the bell - it gives you fine-tuned control over which overtones ring and which don't. The other is a larger magnet that does the same thing as the smaller one, except the added mass can actually change the pitch of the cowbell as well!