These models are precision optical components associated with optics or semiconductors. 

The characteristics are as follows:

 Material and Texture: 

The main body is made of metal, exhibiting a silver metallic luster, with a smooth surface and fine machining texture, indicating high processing accuracy conducive to ensuring stable optical performance, as well as a certain degree of wear resistance and environmental interference capability.

 Structural Form: 

The components are cylindrical in shape, typical of optical lens parts, and this symmetrical structure facilitates installation and alignment of the optical path. The larger part on the right features a flange-style interface for easy mechanical connection to equipment; the smaller cylindrical part on the left may be a matching small lens or optical accessory, with the size difference reflecting the different functions or application scenarios. 

Optical Window:

One end of the larger cylindrical part has a transparent optical window (presumably where the lens is located), with finely machined edges, showing no obvious burrs or defects to ensure efficient light transmission, reflecting precise design for the optical path, and is a key part for achieving optical functions (such as imaging, detection, etc.). 

Detail Design:

The surface has details such as scales and markings, possibly for model identification, installation calibration, etc. Small holes and interfaces on the side may serve purposes like pressure equalization, aiding installation, or optical path debugging, reflecting a balance of functionality and practicality in the design.