Steps for installing tray supports in the closure base or adapters. Instructions for assembling adapters, tightening bolts, and performing. Describes the 3M™ 2178-L/S Series Fiber Optic Splice Cases and their applications. With one of the most extensive fiber closure portfolios, 3M f take the first steps in protecting your fiber optics. If damage occurs, cut back sheath to adequa or armor, if present). 3MTM Fiber Optic Splice Closures 2178-L/S Series 3MTM Flame Retardant Fiber Optic Splice Closures 2178-L/S/FR 3MTM Cable Addition Kit 2181-L/S 3MTM Flame Retardant Cable Addition Kit 2181-L/S/FR 1.