Denier is a unit of measurement that represents the fabric’s thickness. Blanket labels often say “1200D,” where the D stands for Denier. Low denier blankets are often lightweight and have a lesser thickness. High denier blankets are thick and constructed of durable fabric. The Denier count also reflects the blanket’s durability. Thicker materials, in general, are tear and cut resistant, therefore they will last a long time.