Physically, this unit is made in mirror-imaged pairs and is designed to mount directly on the binding posts of Decware amplifiers.  The spacing is standard so they may work on many non-Decware amplifiers as well.  Sometimes they are connected to the speaker binding posts instead of the amplifier -- electrically either way yeilds the same result.  
 
Electrically this network goes in series with the positive lead of the Fast-15 driver.  It has only three parts, all in parallel.  The total resistance is 0.36 ohms so it is barely there.  Transparency is top notch. 
 
Gives the driver flatter top end response for extended listening enjoyment.   Unit can be soldered like any other crossover, or used as shown connected to the amplifier binding posts. 
 
Board is designed with double thick gold traces.
 
Price is for one pair.