A stopcock is a form of ball valve that is used to control the flow of liquid or gas. It is coarse and its use is confined to on-off applications. A 3 Way Stop Cock Consists of intravenous sets and related things. The cock is sterile in nature and is perfect for single use. It consists of 2 female Luer ports and a male Luer lock. All the three ports are capped. All the colored studs are provided and may be attached for color coding purposes.