An article can include a protective core having two end portions. The article can include a number of support cores. Each support core can be positioned substantially adjacent each end portion of the protective core. The article can include a cold shrinkable material held in an expanded state over at least a portion of the protective core and at least a portion of each support core. The support cores, the protective core, and the cold shrinkable material can collectively be placed over an apparatus such that the cold shrinkable material tightens over a portion of the apparatus responsive to removing the support core from the cold shrinkable material.