Ultrex accumulating sleeves are hard plastic sleeves that fit loosely over a roller. The main purpose of Ultrex accumulating sleeves is to allow powered conveyor rollers to accumulate product without causing damage to the rollers or the product.There is enough friction created between the conveyor roller and sleeves that products can be conveyed as normal even though the sleeves are not tightly fixed to the rollers. When products are stopped the sleeves are free to stop with the product which prevents damage to the product.  The rollers continue to operate inside the accumulating sleeves.  The smooth surface of the Sleeves slides freely over metal rollers without damaging the sleeve or the roller.