3M™ Cold Shrink Foldback Splice Jacket Kits SJ-FB Series are a series of folded back, tubular rubber sleeve that combined with Scotch® Rubber Mastic Tape 2228 provide a sealed jacket over cable splices installed on Jacketed Concentric Neutral (JCN) and other types of jacketed power cable. 1.15" Minimum Cable Jacket O.D., 3.25" Maximum Cable Splice O.D., 30" Maximum Cable Jacket Opening.