Use this kit as a keychain, whistle, and a secret compartment for bill storage - easy to make - very practical! 10mm tube, 2-9/16" long. The Chrome plating is ultra hard, gives a superb substrate adhesion, has a bright, attractive finish, and is stable and noncorrodable. It also gives ultra high metal-to-metal sliding wear resistance and provides superb abrasion resistance, even under high contact stresses. Plus it gives a very low wear rate (at least 100 times better than hardened steel or electroless nickel).