Switching Split Power Supply ± 12V 500mA Split Supply

I know you just did a double-take when looking at this power supply, what's up with the two cables? Normally you have a switching power supply that

AC 100-240V to DC 12V 2A 2000mA Power Supply Adapter Switching +4 Split Power Cable for CCTV Security Camera DVR NVR LED Strip UL Listed FCC

Switching Split Power Supply ± 12V 500mA Split Supply : ID 2591

I.T.E (12V500MARS) 12V 500mA Switching Power Supply Only **READ

12V DC 500mA Switching 100V-240V CCTV Camera Power Supply AC to DC Power Adapter

Switching Power Supply - 24V 500mA - TOL-08981 - SparkFun Electronics

Dual Power Supply

Review Request] Split Power Supply for Headphone Amp : r

I.T.E (12V500MARS) 12V 500mA Switching Power Supply Only **READ

US AC/DC 12V 0.5A 500mA Switching Power Supply Cord adapter 3.5mm