12 coils of bright Stainless steel memory wire 0.62mm (0.025) wire. Coils 5.7 to 6.7cm diameter (2.25 to 2.63 inches).

The wire is very hard and springy, but can be worked with pliers. Finish with end caps or make loops with round nosed pliers. 
You may wish to try forming an addition loop in the centre of the wire to add charms.

This is the middle of the three sizes as shown in the photo.