Talking to B&F at the Welsh Game Fair, the 'new' red box has 3 aeriels inside, 1 runs the length top to bottom, 1 runs the width left to right and the other runs the depth from front to back, this is to give as much accuracy as possible to search and find. The collar signal runs through the length from the red connector to the black and extends in that straight line so the box will take you to the signal line before taking you in towards the dog.
I enter the dog, put the box over the hole and wait for either the reading to settle down or baying then I move in.