A menstrual cup is a menstrual hygiene device which is inserted into the vagina during menstruation. Its purpose is to collect menstrual fluid (blood from the uterine lining mixed with other fluids). Menstrual cups are usually made of flexible medical grade silicone, latex, or a thermoplastic isomer. They are shaped like a bell with a stem or a ring. The stem is used for insertion and removal. The bell-shaped cup seals against the vaginal wall just below the cervix. Every 4–12 hours (depending on the amount of flow), the cup is removed, emptied, rinsed, and reinserted. After each period, the cup requires cleaning.Unlike tampons and pads, cups collect menstrual fluid rather than absorbing it. One cup may be reusable for up to 10 years. This makes their long-term cost lower than that of disposable tampons or pads, though the initial cost is higher. Menstrual cups are also promoted as more practical and eco-friendly than pads and tampons. Given that the menstrual cup is reusable, its use greatly decreases the amount of waste generated from menstrual cycles, as there is no daily waste and the amount of discarded packaging decreases as well. Most menstrual cup brands sell a smaller and a larger size. Some menstrual cups are sold colorless and translucent, but several brands also offer colored cups.Menstrual cups are a safe option relative to other forms of menstrual hygiene.