EPM AGT100 Beer Cap Transducer Acoustic Guitar Pickup. An excellent entry-level contact transducer. The patent-pending transducer head fits neatly in to a beer cap, with many designs available. It attaches simply and easily to the guitar body with a reusable adhesive that will not mar or affect the guitar surface. A short cable with a 1/4" female connector is attached. The EPM evolution has been creating better sound for acoustic guitar players for more than ten years.