Shrinkable sleeve is applied to the optical fiber closure to fix and protect the optical fiber when splicing. The sleeve can be divided into two types (sigle and mass)according to the function.The single type is used for the single-fiber,and the mass type is used for the ribbon fiber.it is different in the reinforcement between two types. The single one realizes the reinforcement by the stainless steel needles,the later one via the ceramic reinforcement member to realize the function. Mass means there are several cores for the fiber. so the mass sleeve includes 4cores,6cores,8cores,12cores(for types). Mass type sleeve Materials: 1.Hotmelt adhesive 2.Ceramic reinforcement member 3.Heat shrinkable tube Single type sleeve Materials: 1.Hotmelt adhesive 2.Heat shrinkable polyolefin 3.Stainless steel needle