The Curt Class I trailer hitch # C11124 does not come with the appropriate ball mount. The correct ball mount for this hitch is # C45520. I checked your order and it looks like you did order it so you chose the correct one.
Then use # F-4 for a pin and clip and for a 1-7/8 inch ball use # 19256 or for a 2 inch use # 19258. view full answer...