Nb-50-9B Review of the $20 RFID mouse- Designed with A4Tech’s Innovative Radio Frequency Identification Technology. This Battery-Free Wireless Optical Mouse is absolutely Interference-free from any wireless frequency. In addition to that, the RFID Mouse Pad is directly power activated & the mouse creates huge cost saving for its users. Most importantly, this technology avoids unnecessary pollution caused by batteries. [via] Link.