Heating spirals is a resistance wire rolled onto the proper core and ending with an electric outlet in the form of a wire twisted pair (often referred to as the "plait") or a current pin.
Basic information:
A high quality resistance wire Kanthal by Sandvik (mainly the grades D,A,A-1,AF,AMP,N80)
A wide selection of diameters (starting form 1mm) and power
An electric outlet in the form of a "plait" or pin