The Cocoon Auto Retainer is designed to prevent trip hazards by retaining the sling/sack cord in the housing with the use of spring loaded mechanism, this increases the safety of the fish between water and mat. The cord can stretch to 4.5 metres, but can be locked as shorter distances. By pressing the thumb lock the sling/sack and fish will be draw towards the bank automatically and the cord stored in a tangle free state until next use.