It is black, with 4 holes it it, and a red plug.
Hey there
The horn you have WILL work with the Internal Magic Pie kit
If you purchased the 'black' one with 4 holes in it as you described then it is a 24-72v scooter horn.
To connect this, connect the
red wire from the horn to the red 'led light' wire from the cable harness. Then connect the
black wire from the horn to your switch wire 1, then switch wire 2 connect to ground.
So when you apply the switch, it will connect the Ground signal to the horn to allow it to function.
If you want to use the red 'push on/off' switch that is on your throttle (yellow + brown wire) then connect as described above, using the brown wire for Ground signal, and yellow connected to horn black.
The 'red' colored horn (siren) is an inducer that needs AC to work, this is the type that plugs directly into the external controllers and cannot be used by internal Magic Pie.
Toot toot !