Up until now, when you wanted to build a co-phase harness you would use a PL-259 without an insert.  It got the job done but you would end up with a lot of slop between the coax and the connector.  That was then ... 

This is now! This special (and hard to find) PL-259 connector is made for nothing else but co-phase harnesses. 

It has two holes in the base for inserting each piece of coax.  There are soldering access holes on the side for making that all important connection and the tip uses the regular soldering procedure.

Only the connector, no cable