The implant (Implanon or Nexplanon are the brand names) is a teeny-tiny rod that's inserted under the skin of your upper arm. It's so small, in fact, most people can't see it once it's inserted—which means it can be your little secret, if you're so inclined. The implant releases hormones that keep your ovaries from releasing eggs and thicken your cervical mucus, which helps to block sperm from getting to the egg in the first place. Plus, it prevents pregnancy for three years. Not too shabby.