Sea Dog Hatch Spring, spring length: 8-5/8". This Hatch Spring has an internal wire that prevents the spring from being overextended during normal use. Constructed of corrosion resistant formed 304 stainless steel. Installs with four #6 RH fasteners or 1/8" pop rivets (not included). Not recommended for applications where hatch will scoop wind while boat is underway and overextend spring.