This is a simple little project to create a dual-voltage power supply for use with dual-supply op-amps. It uses a RZC12W20 IC to create +/-12v from a 5v (USB) source.
The RZC12W20 is designed for creating a dual-voltage supply from the 5V rail at PCB level. The '12' indicates the output voltages, and 'W20' indicates 20W power rating, It requires no additional components, so this project consists of soldering the IC to a piece of prototype board, creating input and output connectors, and putting it in a case.
The input connector selected here is USB cable from a mouse, and the output is a 4-pin screw terminal.
20W means it should cope with about 0.8A per side, but it is not clear what heatsinking the quoted rating assumes. In this application it will be used at about 300mA per side.