A small, sterile, stand-alone, Luer-activated needleless plastic valve intended to mate two related intravenous (IV) line devices [e.g., hypodermic syringe and catheter port or tubing from an IV administration set] and hold them in a secured, sealed, locked position until disconnection, at which point negative pressure from the device causes a small volume of retrograde fluid flow into the catheter/tubing. It is intended to eliminate the use of needles for IV administration of medications. This is a single-use device.