Contains a single electric guitar string, magnetic pickup with 4mm connections. It is a low profile unit, just 25mm high so that it can fit under a sonometer wire. Constructed in clear acrylic measuring 80 x 35 x 25mm. Suitable for use with any steel wire system such as a sonometer. The pickup is low-profile and with a typical output. A versatile single electromagnetic pick-up can display the oscillations of a wire on an oscillioscope screen. This provides an alternative to tuning fork resonance when investigating frequency / length or frequency / tension relationships etc.