manner than described herein in regard to the first ballast unit 12 of fig4 and 5 the rear retaining rod 40 is rotatably and removably positioned within a clearance hole of upper rear bracket 48 of upper frame 24 and within a clearance hole of lower rear bracket 50 of lower frame 26 the rear retaining rod 40 is preferably threaded at least at the upper end thereof in this way when the ballast unit 18 is placed in the lower frame 26 and the upper frame 24 then placed on top of the ballast unit 18 the rear retaining rod 40 may be positioned within the clearance holes of the upper rear bracket 48 and the lower rear bracket 50 the rear retaining rod 40 of fig4 and 5 additionally includes at a lower end thereof an angled or hook terminus 52 for removably fixing the rear retaining rod 40 to the vehicle 100 that fixing may be accomplished by connecting the terminus 52 to the frame of the vehicle 100 or preferably by adding a vehicle bracket 54 to the rear end 120 of the vehicle in front of the vehicle bumper 170 if one exists the lower portion of the rear retaining rod 40 may be threaded to provide for the removable fixing the rear retaining rod 40 preferably includes a rear rod handle 56 that is.