Not rubber. Vulcanized rubber.

The difference is molecular. Raw rubber is soft, unstable, and degrades fast. Vulcanization changes that permanently - natural rubber is heated with sulfur under controlled pressure, creating cross-links between polymer chains. The result is a three-dimensional network structure that raw rubber can never achieve.

The TheHive strap is black vulcanized rubber. It doesn't stretch out of shape. It doesn't crack under UV. It doesn't stiffen in cold or soften in heat. It holds its geometry -and its finish - indefinitely.