A three prong clamp rotatable double key is a laboratory apparatus that is used to hold and secure a round object, such as a flask or test tube, in place during an experiment. The clamp consists of three prongs that can be adjusted to fit the size of the object being held, and a double key that can be rotated to tighten or loosen the grip of the prongs.

This allows for easy and precise positioning of the object during the experiment. The clamp is typically attached to a laboratory stand or support rod using a separate holder or adapter.