A thin, match-stick sized rod that’s inserted by a healthcare provider under the skin of a woman’s upper arm. It contains progestin and works by preventing ovulation, by causing the cervical mucous to thicken to prevent sperm from entering, and it makes the endometrium thinner to help prevent implantation. The advantages can include decreased period flow and less cramping. The disadvantages can include mood issues, irregular period flow, weight gain, and a decrease in bone mineral density. The failure rate is .4% or 4 out of 1,000 women.