The signature FCS fin from Matt Biolos. The MB is from the Reactor fin family, so it has a lot of pivot for tight turning and is very fast. The Carbon construction is extremely light and rigid.

Sitting in the Reactor Family, the FCS II MB is considered a high performance fin because it responds incredibly fast, but still offers enough control so you can confidently lay into a turn with plenty of force. With noticeable geometric similarities to the Performer template, but with less sweep, it has a balanced outline with smooth curves and moderate area in the tip. The fin also has a relatively short base in contrast to the higher depth value of the fin. The same template features across all three sizes.

When you enter into a turn, this fin will respond without delay. It’s a very versatile template that’s perfect for making acute directional changes in hollow sections, while providing enough control for advanced surfers performing at the highest level.
The high depth value of the fin also provides great down-the-line stability, and has just enough bite when venturing out on the open face. The large size MB is particularly good for heavier surfers looking for a high performance fin.

Performance Core Carbon (PCC) has the fastest response time of all the FCS fin materials. MB’s fins have been updated with a carbon tissue inlay that gives the fin a very uniform flex pattern from base to tip, and provides a very positive feel when turning. The small and medium sizes have also been spec’d with a touch more flex in the top 1/3rd of the fins to better suit these weight classes.
“Mason Ho is the surfer who probably uses my fin the most and is a good example of the speed and flow of this fin, with his ability to break off track real quick for reactive, spontaneous surfing. A fast, forgiving fin that’s fun for everyone.” - MATT BIOLOS