NX 6710 Defender is a grey dye blocker to be used a direct print first down userbase or a last down backers for cold peel transfers. Either way they block dye molecules in 100% polyester dark colored garments that are prone to dye migration. The particles contained in the blocker act as filters to stop dye molecules that try to migrate up through the ink film during the curing or heat transfer process. NX 6710 will prevent dye migration on most 100% fabrics but it may be necessary to use NX6711 when printing on 100% known to be nasty blended fabrics.