The chip, just 20 x 20 x 7 millimetres, is designed to last up to 16 years -- about half of a woman's reproductive lifespan -- delivering a daily dose of 30mcg of levonorgestrel, used in several hormonal contraceptives and emergency contraceptives. In the event a couple wants to conceive, the woman can use a remote control to turn the chip off, and then back on again when she needs to.