This is a Paramount PMHSFSKL15S Hot Shoe to Male Screw-Lock PC Sync Cord. It is a 15' (4.5 m) long, straight, non TTL cord with a screw-lock PC tip for cameras or flashes that are equipped with a screw-lock PC terminal.
Possible scenarios for use are:
If your camera has no hot shoe.
You wish to fire a second, standard hot shoe flash far from your camera's PC sync terminal.
Note:Sony/Minolta flashes cannot use this item without an additional shoe adapter