What is the difference between Oxford Polyester 250 den and Oxford Polyester 500 den?

Denier (abbreviated D) is the unit used to describe the weight and thickness of textiles.  Fabric with a higher denier is thicker, stronger and more durable than the same fabric with a lower denier. The Oxford Polyester 500D (used for the Premium and Pro range tops) is therefore stronger than the lighter alternative of 250D (used for the Comfort tops and all side panels). 

At Canopy, we consciously choose to describe the weight and thickness of fabrics in deniers instead of grams. The reason therefore is that the total weight of the fabric can be strongly influenced by the treatments and coatings applied to the fabrics.  Textile manufacturers use different products to make their fabrics waterproof, rot and UV resistant, and fire retardant. Sometimes additives are added to the fabrics. These products make the fabric heavier without strengthening it. A heavier fabric does therefore not automatically mean that it is stronger.