Cannulight Technology Limited

Cannulight is a small, lightweight, sterile, single-use, disposable device that fits onto most standard IV catheters. The moment the needle enters the vein, the device lights up green, giving clinicians instant confirmation of success. If the catheter needle double punctures or exits the vein, the light turns off. If the needle is then repositioned back into the vein the light will turn back on, and the procedure can be rescued restoring both patient and clinician confidence.

From the manufacturer's own website. Source