Another cool design that i found on the web - handcuffs bracelet with some rocky vibe. Easy to rig by adding some hooks at curve control points. As far as i know all of material textures are free to use, exept environment texture - you can download higher resolution one here http://gl.ict.usc.edu/Data/HighResProbes/ but i'm not sure about its terms of use.

Preview picture was rendered using Filmic Color Management at basic settings, just basic contrast, so if you want to get the same colours and saturations at your render result you need to install this addon. You can visit Andrew Price's Blender Guru tutorial called 'secret ingredient to photorealism' to learn more about Filmic. Pretty cool stuff.

https://vimeo.com/267872646
Enjoy!