This is only the driver side (left side) installation kit. The corresponding passenger side (right Side) installation kit is 221RH.
http://www.unityusa.com/221RH-Installation-Kit_p_789.html
This is used on 1985 Ford Mustang with a spotlight with a "V" length shaft.
http://www.unityusa.com/V-Shaft_c_1574.html