If the results in the wind tunnel are to be believed, placing blunt objects behind smooth ones reduces drag.
This A700 mounts into the back of the fork crown that is normally occupied by the 5mm allen fitting bolt. They are compatible with all brake levers, and most but not all bikes - the Look 496, Trek TT, and the Scott CR1 aero fork aren't compatible.
The cables connect to the brake arms using a rigid section of cable, called a 'noodle' , that is bent at a right angle for convenience. The cable stop rounded so we had to obtain a solderless nipple, and the aerodynamic benefit of fitting the rear brake is minimal for most types of rider.