In the video, a person is seen holding a knife in their hand. The person is using their thumb to push down on a button located on the handle of the knife. This action causes the blade of the knife to extend outwards. The person then releases the button, and the blade retracts back into the handle. The person repeats this action several times, extending and retracting the blade with the push of a button. The knife appears to be a folding knife, and the person is demonstrating how to open and close it using the button on the handle. The knife has a black handle with a silver blade, and the button is located near the base of the handle. The person's thumb is visible as they press down on the button, and the blade moves smoothly in and out of the handle.