They accommodate up to 12 fibers (250-micron coated ribbon). The outer tube is made of ethylene-vinyl acetate. A Fiber Optic Splice Sleeve is a protective tube designed to encase a fusion splice—the point where two optical fibers are joined together. It comes with an ethylene-vinyl. manufacturer of the industry's highest quality and most extensive line of fiber optic fusion splice protection sleeves available with millions in service worldwide. The FP-03 series is the industry standard for durable and lasting protection of single fiber splices in field installations, while the. This product is made up of cross-linked polyolefin heat-shrinkable tubes, hot melt tubes, and stainless steel needles.