Here is a summary of the main PC parts found in Akihabara from February 23 to February 28, 2015.
Rooter "RT-USBVATM
1,080 yen (including tax): PC House Toei
1,180 yen (including tax): Techno House Toei
Low-priced model of voltage and current checker for USB devices.
It is connected between USB power source and USB devices, and features the ability to display voltage and current values as well as total current values (up to 99,999mAh) and energized time (up to 99 hours).
The main specifications are as follows: main unit size: 72 (W) x 23 (D) x 13.5 (H) mm, weight: approx. 18 g. Measurement range: voltage: 3.5 to 9.0 V, current: ~3.3 A. Measurement error: +/-1%.