Removable hitch ball mount. Ball mount measurements: Length equals the distance from the center of the ball hole to the center of the pin hole. Drop equals the distance from the top of the shank to the top of the ball platform. Rise equals the distance from the top of the ball platform to the top of the shank. No. 21171: Class: III, Receiver Opening Size: 2 In., Hitch Ball Hole Size: 1 In., Drop: 2 In., Rise: 3/4 In., Length: 9 In., Tongue Capacity: 600 Lb., Trailer Capacity: 6000 Lb., Finish: Metal Shield, Pkg Qty: 1 No. 21175: Class: III, Receiver Opening Size: 2 In., Hitch Ball Hole Size: 1 In., Drop: 3-1/4 In., Rise: 2 In., Length: 9-1/2 In., Tongue Capacity: 500 Lb., Trailer Capacity: 5000 Lb., Finish: Metal Shield, Pkg Qty: 1 No. 21186: Class: III, Receiver Opening Size: 2 In., Hitch Ball Hole Size: 1 In., Drop: 5-1/4 In., Rise: 4 In., Length: 10 In., Tongue Capacity: 500 Lb., Trailer Capacity: 5000 Lb., Finish: Metal Shield, Pkg Qty: 1 No. 21342: Class: III, Receiver Opening Size: 2 In., Hitch Ball Hole Size: 1 In., Drop: 2 In., Rise: 3/4 In., Length: 8-1/2 In., Tongue Capacity: 600 Lb., Trailer Capacity: 6000 Lb., Finish: Metal Shield, Pkg Qty: 1 No. 21347: Class: III, Receiver Opening Size: 2 In., Hitch Ball Hole Size: 1 In., Drop: 8 In., Rise: 6-3/4 In., Length: 10 In., Tongue Capacity: 500 Lb., Trailer Capacity: 5000 Lb., Finish: Metal Shield, Pkg Qty: 1 This item replaces product number 141978