This is the Apollo Retractor (auto retracts lights, gauges, etc.)

Features:

• Apollo Retractor Special Features:
• Auto Return
• Arms length pull
• Plastic Loop or 2 Slot for webbing
• Fitting: Standard 2" slot for easy installation on most BCD straps and weight belts.

Auto return gauge and accessory holder. Dangling gear can act like a wrecking ball, chipping off bits of coral, knocking loose sponges and catching at the most inopportune time. Keep your gauge, and other gear securely tucked away when not in use. Retractor allows you to instantly pull any item out to arms length for use. Automatically retracts to original position."