The birth control implant is a small, flexible plastic rod measuring 1.6 inches (4 centimeters) in length—about the size of a matchstick. It is inserted under the skin of the upper arm and remains there throughout its duration of effectiveness. The implant is quite slender, typically 2 millimeters in diameter, making it barely visible once placed beneath the skin, though it may be felt if you press on the area where it's inserted. Despite its tiny size, the implant releases a steady dose of the hormone etonogestrel (in the most common version, Nexplanon) directly into the bloodstream over a period of years. The insertion procedure itself takes only a few minutes and is performed by a healthcare provider using a special applicator. The implant can be removed at any time by a healthcare provider, and fertility typically returns quickly after removal. Users can often see or feel the outline of the implant through the skin on their upper arm after insertion, and some people report being able to feel it when they press on the area, though it should not be visible as a lump. The small physical size is one of the advantages of this contraceptive method—it's discreet, requires no daily action, and is one of the most effective forms of reversible birth control available.