The difference between the Multicouplers is that the VHF/UHF version has a high pass filter on the input to filter out HF signals.
The VHF/UHF version is usually sold to customers at or near airports to monitor airband traffic 24/7. They may have a HF radio on site that they need to filter out of the VHF system.
The HF/VHF/UHF version is a favourite of radio amateurs and airband listeners. It allows them to use it with different antennas and a wide range of receivers for whatever project they are experimenting with.
There is no difference in performance between the two versions other than the HF filtering.
As we are about to build a large batch of Multicouplers for stock during the coronavirus outbreak we will probably only make the HF/VHF/UHF version rather than try and stock multiple options.