A sleeve kit has a case, multiple sleeves and a cover. The case has multiple sleeve brackets and multiple fasteners. Each fastener is mounted on a position between two adjacent ones of the sleeve brackets, protrudes from a plane where openings of the sleeve brackets are located and has two barbs and a gap. The cover covers the sleeve brackets and has multiple secure holes respectively mounted around the fasteners. With the secure holes mounted around the fasteners, the cover is difficult to be removed from the case, and the sleeves are protected against burglars.