KastKing Kovert Xtreme Fluorocarbon Fishing Line - KastKing Kovert Xtreme fluorocarbon fishing line is engineered using Japanese PVDF resin. Designed with lower stretch and higher abrasion resistance. Kovert Xtreme fluorocarbon fishing line loads differently than traditional monofilament, requiring greater force to stretch the line. Kovert Xtreme is exceptional when used as a main fishing line or as a leader material.