Most filters supplied or bought by home users have the plug part built in to the filter, whilst 'professional' models have a wire tail between the filter and the bit that plugs in to the phone socket. is it just to make them look different or doe the use of a tail have technical benefits?
No one has to agree with my opinion, but in the time I have left a miracle would be nice.
There is no difference in how they work. The only reason for the 'tail' is because the main box part is too big so needs to hang below the socket it plugs into. In general the 'tail' based products are better quality in that they use more and better quality components.
I'm parading my ignorance 