These kits contain everything for installing a simple, variable system.Keep your mainsail under control and on the boom as its lowered. Works exceptionally well with fully-battenedmains, but can also be used with conventional sails. Harken Lazy Jacks are designed to contain and restrain the mainsail while reefing and furling. Can be quickly detached from the boom to permit the use of a sailcover with slots. Everything you need to install a simple, adjustable system is included in the kit: pre-swaged wires, blocks, eyestraps, line, a cleat, fasteners and instructions(including how to alter your sail cover for use with lazy jacks).Key FeaturesKits contain everything for installing a simple, variable systemWorks with fully-battened mains and conventional sailsIncludes pre-swaged wires, blocks, eyestraps, line, cleat, fasteners and instructionsLazy jacks make mainsail flaking and dousing easyKeeps the mainsail on the boom as its loweredApplicationsSmall Boat Boom Length: 7' to 13' (2.13m–3.96m); mainsail luff length: 21' to 32' (6.4m–9.75m)Medium Boat Boom Length: 10.6' to 16' (3.2m–4.87m); mainsail luff length: 32' to 42' (9.75m–12.8m)Large Boat Boom Length: 12' to 16'. (3.7m–4.9m); mainsail luff length: 35'7" to 48' (10.88m–14.63m)