What is the difference between a click-clack drain, grid drain, and pop-up drain?
The difference lies in the way the drains are opened and closed.
Refer to this doc: The difference between click-clacks and pop-up wastes
A click-clack drain (item #7100-16), also called a touch drain, is a domed drain where the user pushes down on the dome to close the drain and pushes it again to open it. Although the grid drain (item #7100-13) looks the same as the click-clack drain, the grid drain does not close and will allow water to drain out at all times. This type of drain is the most commonly used in settings where you do not want the sink to be filled with water, such as in a commercial setting. Grid drains are also recommended for very shallow sinks or sinks without an overflow. The pop-up drain (item #7100-12) opens and closes by attaching its horizontal rod to the pop-up rod found on the back of most deck-mounted faucets. If the faucet does not have a pop-up rod, then the pop-up drain would operate by lifting and lowering its handle below the sink. This drain can only be used with sinks that have an overflow.
