This is a multi-pack, or "combo set," of four long-sleeve, solid-color shirts from Calvin Klein. The shirts appear to be made of a smooth, casual-wear cotton fabric. Each shirt features a classic button-down collar and a single chest pocket on the left side.

A key design element is the embroidered "ck" logo on the chest pocket of each shirt. The stitching is in a contrasting dark thread, making the logo stand out on the lighter-colored shirts. A hangtag for the set, featuring the full "Calvin Klein" brand name, is prominently displayed, indicating a bundled product.

The color combination in the set includes:

 * Top shirt: A light gray or taupe color.

 * Second shirt: A bright, light blue.

 * Third shirt: A dusty or muted green.

 * Bottom shirt: A classic black.

The style is versatile and well-suited for a casual or smart-casual look.