Canon TC-80N3 Remote Cabled Shutter Release. In the box.
This is a used item with a couple of very light marks. See photos. EOS-1D, 1D Mark II, 1D Mark II N, 1D Mark III, 1D Mark IV. EOS 5D, 5D Mark II, 5D Mark III, 5DS, 5DS R, 5D Mark IV. EOS 6D, 6D Mark II.