"EPM Corporation: The Cap - AGT 100 Stick On Contact Transducer Pickup"

Cap design varies.

It attaches simply and easily to the Guitar body with a re-usable adhesive that will not mar or affect the Guitar surface.

Suitable for use with a variety of acoustic instruments, from Guitar to Violin.

The patent-pending transducer head fits neatly into a beer cap, and dozens of breweries...