Oh crap! That converter comment is a typo and shouldn't exist (hence removed). I believe the convertor is this wire harness "box" that you attach to the underside of your car - sort of like an electrical socket. Makes it easier to manage wires since they're modular - no dangling wires.
I can carry 3 bikes. Checkout my CarDomain page in my sig...there might be a partial picture with it shown.
The ball is just that. A ball attached to a steel post that you insert into your hidden hitch. You see, the Toyota hitch that attaches to your car is just a heavy steel crossbar with a square peg-hole in the middle. You can put anything in that peg-hole...a bike rack...ski rack...or a ball. The ball would be if you had a trailer and wanted to carry your Sea-Do from lake to lake.
If you're in the Toronto area, PM me and I can show you in person.