Technical Radius Rods (TCI Frame)

Looking at the TCI website: 33-34 Ford Dropped Front Axle, 4 Link Rearend, there are several options for the front axle which seem pretty straight forward, but there is also an option for radius rods. According to the website, the ch***is comes complete - so what are the optional radius rods?

Yes, I can call TCI tomorrow and ask - I got home too late today and figured someone on this forum would know.

Thanks

 

I think the option is hair pin style radius rods as compared to the standard four bars they sell.

 

Thank you