Full Idea
The static (B-series) theory, by embracing the relational temporal properties 'earlier' and 'later', adds a directional ordering to the block of events.
Gist of Idea
The B-series adds directionality when it accepts 'earlier' and 'later'
Source
Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Time's')
Book Reference
Bardon,Adrian: 'Brief History of the Philosophy of Time' [OUP 2013], p.112
A Reaction
I'm not clear whether this addition to the B-series picture is optional or obligatory. It is important that it seems to be a bolt-on feature, not immediately implied by the timeless series. What would Einstein say?