4-USB 5V 5A Step Down Module Power Supply Charger Module, AU$6.54
*Support multiple devices to use at the same time.
*Automatic buck module, provide a stable power supply.
*Applicable to unstable voltage source or voltage conversion.
http://www.icstation.com/output-step-down-module-automatic-b…
DIY Kit Ultrasonic Range Finder Distance Measuring Transducer, AU$6.44
*Supply voltage: DC 4.5-6V
*Detection range: 25-400cm (indoor)
http://www.icstation.com/ultrasonic-range-finder-distance-me…
Tips: Free shipping for order reached US$20 (AU$26.39)
If the order amount is less than $20, then there will be extra $5 (AU$6.60) for shipping (insurance register airmail tracking number service).
Can someone explain what this step down module is for please. I was looking for a USB power brick to power several USB devices. Is this what I want?