**Main Fabric:** The outer layer consists of abrasion-resistant nylon/Oxford cloth—waterproof, breathable, and tear-resistant. The inner layer utilizes breathable mesh fabric to enhance airflow, accelerate heat dissipation, and prevent moisture buildup against the skin.

**Core Design Features:**

**Back Phase-Change Zone:** The center of the back features a transparent/translucent gel zone with a diamond-grid pattern (housing an embedded PCM phase-change gel plate); this design ensures high heat absorption efficiency and prevents the gel from clumping.

**Dual-Side Adjustment:** Both the left and right sides are equipped with black nylon buckles and adjustable straps, allowing users to freely customize the fit according to their body shape, ensuring a snug fit and preventing slippage.

**Non-Slip Shoulder Straps:** The shoulder straps feature a widened design with a non-slip textured surface, reducing pressure on the shoulders and ensuring a more secure and stable fit.

**Cooling Principle:** Leverages the physical property of **Phase-Change Material (PCM) Gel**—specifically its ability to absorb a significant amount of heat as it transitions from a solid to a liquid state—to continuously draw heat away from the body, thereby maintaining a stable temperature within a comfortable range.