(Please click image for larger picture) The Ultramarine was developed as a multipurpose amphibian knife plus it is able to transition to a tactical field knife. To accommodate this multi-facet use, the knife comes with two sheaths: one is a dive sheath and the other is a field sheath. The hard inner sheath is made of ABS and the outer sheath is made of Polyamide (Nylon). The weight of the sheath is g 280 (9.88 ounces) The Ultramarine sheath is a specially designed sheath. It is designed to stay close to your body so that it doesn't get entangled. The sheath has a quick release so the knife can be drawn quickly after pulling on the upper portion of the protective flap. Special “anti-wet” snap fasteners are used on the protective sheath flap. It is the responsibility of the buyer, not Xtreme Knives, to determine and follow all local, state, federal and international laws and ordinances regarding the purchase, possession, and use of any item purchased from us. Copyright 1999 - 2010 Xtreme Knives (tm). Xtreme Knives is a trademark and division of DataForge.cc. All rights reserved worldwide.