Summary

http://youtu.be/cugBD34WTY4
This is a bracelet designed for printing with Fenner Drives SemiFlex (makers of Ninjaflex filament). This design features 20 spikes that are lined up in rows and positioned at an angle. The bracelet features a "snap-in" nubs on the edge that locks into slits on the opposite end. Prints great using SemiFlex but also works well with Ninjaflex.

NinjaFlex
http://www.adafruit.com/product/1690

SemiFlex
http://www.adafruit.com/products/2321

For more information on using NinjaFlex
https://learn.adafruit.com/3d-printing-with-ninjaflex/overview