This item has been shown 7 times.
says "C 4/0" on them..
please see photos.
the cup receiver is 0.62 inches inside diameter.
and 0.81 inches outside diameter.
Very Thick Bolt on it.
its 0.61 inches in diameter =15.55mm
threaded part is 2 inches long.
total length is 4.5 inches
weigh 1/2 a pound each.
Sold as is.