This is a quad S2 tuner that replaces the TBS6984. Adam currently uses one of these that was donated by TBS to provide more tuners so he had some available for development without interfering with his live system.
Unlike the TBS6984 though it does not suffer from the massive concurrency problems that have been discovered with the TBS drivers and are detailed here. This is mostly down to the fact that it has 4 completely independent tuners rather than a pair of pairs (the TBS6984 is basically 2xTBS6981).
The one issue that is still common on this device is that the default interrupt handling mode can cause the device to stop working after a random period of time. To overcome this you need to enable MSI interrupts (assuming your MB support it, VERY likely).
Run the following:
cat > /etc/modprobe.d/tbs.conf <<EOF options saa716x_tbs-dvb int_type=1 EOF reboot