Drake Race NR 700 vs Drake Race 700

Hello,

I have a Formula 159 with deep tuttle fin box.

Anyone know if the fin base should fill the entire tuttle box ? or can their be a gap between the top of the fin and the deck?

Can I use a Drake Race 700 instead of a Drake Race NR 700 with this board, not sure what the NR means.

Cheers

Dave