What type of wire do U use for jumper ?

What type of wire do U use for jumper ?
What is the diameter size and is it insulated ? I am trying to find one to buy but its hard .. the smallest one in ebay is 0.25 and it is without insulation … is it possible to use the wire from a vibrator motor ? The coil of the cibrator motor ? or some other coil ? thank you in advance