Plug for a sink drain

A plug for a sink drain, said plug having a body with a screw hole fitted to a sink and adapted to receive a plugging element comprising:

• a connector in the form of a tube, a head formed at a top of the tube, and a screw formed at a bottom of the tube and mating with the screw hole of the body, a bore defined in the tube, an orifice defined at a bottom of the bore and having a diameter smaller than a diameter of the bore, and a transverse passage defined in the tube and in communication with the bore;
• a spring having a V-shaped lower portion with two upper tips and two ears extending outwardly and respectively from the upper tips, the spring being configured to be received in the bore of the connector such that the ears extend through and protrude from the passage;
• a cap having a hollow rod defining a lumen and a mouth at a bottom of the lumen and having a diameter larger than a diameter of the lumen whereby a shoulder is formed between the lumen and the mouth, and a plate portion with a flange and a threaded recess formed in a top face of the plate portion and in communication with the lumen whereby an upper shoulder is formed between the lumen and the threaded recess;
• and
• a hollow knob with an opening defined in a bottom thereof and the opening leading to a void configured to receive therein the head of the connector, and a male thread sized to mate with the threaded recess of the cap, wherein, in a lowered mode of the plug the ears of the spring urge against an inner surface defining the lumen and in a raised mode of the plug the ears of the spring support the lower shoulder of the cap.