A higher momme weight means the quality of the fibers in the silk is better, as in the fibers tend to be rounder, longer, more uniformly colored, and denser. Appearance-wise, higher momme silk is usually shinier and more lustrous due to a denser weave. 25 momme silk has a thread-count of 600 plus. 25 momme silk has almost 20%+ more silk per square inch than 24 momme does. This denser weave protects the luster and sheen that silk possess and results in stronger durability. It's estimated that 25 mm pure silk sheets have almost double the life of lower momme weights.