High resolution renders and additional images:
https://disk.yandex.ru/d/oqaAMtXT6pkcsA 

* The collection contains 65 heads of various fasteners (bolts, screws, self-tapping screws, nuts, washers, rivets).
* All nuts are available in two versions - threaded and unthreaded (low-poly versions)
* 5 material options.
* Materials are customized for Corona and Vray. Images were created in Corona Render. For VRay, materials are carefully redesigned for maximum similarity.
* The materials are based on CoronaTriplanar and VRayTriplanarTex. Objects for them do not require unwrapping and, accordingly, do not contain it.
* Low-poly models for mesh smoothing.
* The archive includes low-poly models and low-poly models with additional edges for smoothing the mesh.
* Modifier TurboSmooth (mesh smoothing) assigned to objects through Instance - turn it on / off on one object, and the changes will affect all objects.
* Object mesh topology: quads, triangles (triangles are used in the rarest cases).
* "Pivot" of objects is set at the bottom point (coordinate Z = 0). For some objects the pivot is shifted in accordance with the logic.
* Each material has its own name.
* Each object has its own logical name.

MODEL MESH DENSITY for all objects without smoothing (73 objects):
Low-poly:
- Polygons: 16 046.
- Vertices: 15 882.

Mesh for smoothing:
- Polygons: 32 484.
- Vertices: 32 461.

FORMATS:
- 3ds Max 2015 (Corona)
- 3ds Max 2012 (Corona)
- 3ds Max 2015 (Vray)
- 3ds Max 2012 (Vray)
- FBX (Corona)
- FBX (VRay)
- OBJ
- 3DS
- mat (material library - Corona, Vray)