The model doesn't have bones and IK, the parts are hierarchy linked. It uses helpers for rotation pivots and limits to avoid some rotations (a link should have different pivots for different rotation axis).
The Center helper is for moving, mLink (middle link) is locked and attached to it. Every other part rotates to its fixed pivot.
Verticles: - 5396 one handcuff - 388 and 80 for links
Facets: - 5528 one handcuff - 382 and 80 for links
The links are 1-2 step Nurm Subdivided
Materials: simple Arhitectural Material for Shiny Metal. No mapping required.
Files: - cuffs.max: a zero pose max file for your cuffs. - scene.max, the preview file, a rendered scene using mental ray with a skylight and an area light. Final Gather 25 samples.