Forward Controls Design (FCD) has a knack for taking something good and making it just a little bit better. Their new CNF is a prime example. It is an improved castle nut that is machined from billet 4140PH steel and black nitride processed. It features 4 notches for staking (instead of just three) so that at least three of the notches will be accessible when the castle is torqued. The notches are also deeper, allowing for more secure and consistent staking.
FCD always does a good job of explaining the rationale behind their designs so be sure to check out the CNF at ForwardControlsDesign.com for more details.