The Wonky Wire is used to test the steadiness of your hand. It utilizes a circuit with an oscillator that has a very high oscillation frequency of about 3kHz (3000 cycles per second). As you try to trace the outline of the convoluted wire with the loop, the slightest touch will cause a tone to sound. The variable resistor can be used to change the pitch of the tone. Dimensions: 85 x 76 x 120 mm / 3.3 x 3.0 x 4.7", Weight: 0.1763698096 pounds, Manufacturer: Velleman