Uni-Thread is made from continuous polyester filaments that are slightly bonded and not twisted so they tie virtually flat on the hook.
Denier nylon is a unit of measuring the thickness/weight of a thinly spun fiber. It indicates the material's durability, plus the fineness of fiber filaments and yarns - both natural and synthetic. The higher the denier, the thicker the fiber; the lower the denier, the finer the fiber.