A device intended to be inserted between a syringe and an epidural needle to provide visual confirmation of needle insertion within the epidural space (location confirmation). It is typically a small chamber with a one-way valve and an expandable membrane (diaphragm), and Luer inlet and exit ports. The diaphragm is inflated with air prior to insertion; diaphragm collapse signals entry into the epidural space. This is a single-use device.