Nick Welford: you are correct.
It is splitting the signal from the UHF (Freeview) TV aerial to three TV sockets. It has capacity to supply a fourth socket, and it can also combine the signal from a VHF radio aerial (i.e. FM) into the same downlead system, so you can choose to plug in either a TV or a radio tuner at one of the outlets.
It's there for two possible reasons (not mutually exclusive):
1. The received signal is poor for some reason. This will boost it, usually by 6dB or 12dB (often internally selectable). That's usually enough to get tellys working properly, and it's a bit less critical now we have digital telly (signal quality is more important than signal strength ("loudness").
2. It buffers the separate outputs from each other (or it should!). Signal strength and quality shouldn't be affected by how many of the TV sockets are being used. If it was simply a resistive or inductive splitter, plugging in or disconnecting one TV would affect the others to some extent.
I'm with pcb1962: I don't understand the term "bi-directional" in this context - at best rather misleading. It's just possible it is capable of supplying 12VDC up the UHF aerial input lead (thus "bi-directioal" in an odd sense), which would be used to power a small pre-amp up on the aerial itself (or very close to it). These are needed mainly to improve signal quality in poor reception conditions.
I have a very similar Labgear one (two in eight out).
More modern ones will let you combine signals from a number of different sources - satellite, UHF (Freeview Digital TV), a DAB radio loft aerial and VHF (FM Radio). The UHF-VHF combiner idea (AKA "multiplexer"), like yours is tried and tested over decades.
Although I have one of the more modern ones that supposedly does the whole lot, I've no idea if it actually works well - satellite signals are tiny and pose their own special problems.
If your new property is a flat and that amp is feeding other flats, it really ought to be in a communal part of the property - if you turn it off you'll annoy at least two neighbours! It may just be fdoing outlets in three rooms, but it's unusual to find it 'on display' like that - they normally live in cupboards out of the way (mine is in the attic) - that one looks a bit untidy and either DIY or done by a white van bodger (from the Freeview bubble).
If you only have one TV, and it's in the same room, AND the amp is doing nothing else you need, you can probably remove it altogether and connect the aerial lead straight to your TV (you may need an adaptor, but they're easily had from Maplins and even Toolstation/Screwfix). The signal level will be slightly lower, but that may not matter, depending on local conditions. If it's a nuisance where it is, don't be afraid to try removing it - you can do no harm (but label the cables beforehand, just in case!).
E.