This certification means "the product meets the FSF's standards in regard to users' freedom, control over the product, and privacy." This router being certified today is the TPE-R1100 and is the second router from ThinkPenguin to receive such certification.
The Think Penguin TPE-R1100 runs the FSF-endorsed LibreCMC GNU/Linux distribution designed for embedded use-cases. This Wireless-N Mini-Router isn't designed to serve as one's main router but rather for allowing multiple devices on a network to tunnel traffic through a VPN universally. There is a single WAN and LAN ports on the device along with a USB port.
More details on this mini-router being endorsed by the Free Software Foundation can be found at FSF.org. The mini-router is for sale at ThinkPenguin.com and pricing starts out at $40 USD with a 90-day warranty.