Nape piercing
Somewhat less common are surface anchors, commonly made from surgical implant-grade titanium. A surface anchor has two parts: a base or foot which is inserted under the dermis during the piercing process and which incorporates a stem exposed to the surface, and a decorative disc or ball of jewelry which typically appears flush with the surface of the skin. Surface anchor nape piercings are most commonly found placed symmetrically on either side of the spine at the nape.
Anchor
The best rope for warps is nylon which is strong and flexible. Terylene (polyester) is stronger but has less flex. Both ropes sink, so they avoid fouling other craft in crowded anchorages and do not absorb much water. Neither breaks down quickly in sunlight. Polypropylene or polythene are not suited to warps as they float and are much weaker than nylon and only slightly stronger than natural fibres. They break down in sunlight. Natural fibres such as manila or hemp are still used in developing nations but absorb much water, are relatively weak and rot. They do give good grip and are often very cheap. All anchors should have chain at least equal to the boat's length. Some skippers prefer an all chain warp for added security in coral waters. Boats less than 8 m typically use 6 mm galvanized chain. 8–14 m craft use 9 mm chain and over 14 m use 12 mm chain. The chain should be shackled to the warp through a steel eye or spliced to the chain using a chain splice. The shackle pin should be securely wired. Either galvanized or stainless steel is suitable for eyes and shackles.