All Nash sacks are produced from the original Airflow material that Kevin Nash identified for its superior oxygen exchange, way back in the late 70s. The material is also punched for rapid water drainage when lifting the sack from the water. Other companies offer cheaper sacks made from loose weave mesh similar to close weave keepnets. Nash is totally committed to carp welfare, and will not use the cheaper meshes that let in too much light, causing the carp to become unsettled and stressed. The perfect carp sack is produced from a material that balances maximum oxygen exchange with the darkest possible environment. If you care about carp, use a Nash sack.