The body cord is an integral piece of equipment needed in the sport of
fencing.
The foil body cord has three parts: the weapon plug, the alligator
clip, and the reel plug.
The weapon plug attaches into an opening inside the bell guard of
the fencer's weapon. The foil weapon plug comes in two varieties--bayonet
and two-prong--although there's really no practical difference between
the two.
The alligator clip, so named for its shape, attaches to the back of
the fencer's electrical jacket (the lamé).
The reel plug attaches to, obviously, the reel.
Thus, points scored travel through the foil's wire into the body cord,
where they're transmitted to the reel, then through the floor cords and
into the electrical scoring machine. The alligator clip ensures that
points that your opponent score on your lamé register as being
valid touches and not off-target.
The epee body cord has only a weapon plug and a reel plug. There's
no need for an alligator clip, since epee fencers do not wear a lamé.
Also, the weapon plug and reel plugs are identical and in fact interchangeable.
A sabre body cord is identical to the foil variety. (Thank you mysterious editors!)