Metric Halo LIO-8 was released on 03/25/10 stands for Line In Out (as opposed to MIO Mobile In Out)
It is a lower cost option to the ULN-8 and was achieved by removing the ULN-R (remote) preamps, and removing the +DSP license. Both of these options can be added at any-time as field upgrades, and bring the price in-line with a fully featured ULN-8.
There are no physical or quality differences between a ULN-8 stock, and a LIO-8 with upgraded pre-amps, and +DSP. (except that the MIO Console software will always show the unit as LIO, not ULN).