A sheath is a must for any normal knife. Always replace the knife in its sheath when not in use, even if only for a minute or so of inactivity. A sheath should be made from strong, stitched leather, with a tunnel belt loop. Ensure that it has a positive fastening to secure the knife. Some sheaths may have additional small pockets for a penknife or a sharpening stone. These could be useful to have.