SKU: 40938628003

FCS II Surfboard Fin Boxes 0o 3o 5o 9o

Sale price$12.60 Regular price$14.00
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  • USA
  • CAN

Ships within 48 hours · Estimated delivery Jul 19 - Jul 24

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Description

FCS II Surfboard Fin Boxes 0o 3o 5o 9oFCS II Surfboard Fin Boxes 0 o 3o 5o 9 o Efficient keyless system for quick fin installation and release. The FCS II system requires no grub screws or keys to secure the fins to the board. Fins can be easily inserted and removed in seconds, allowing you to adapt your equipment to the conditions, on land and in the water. Recessed leading edge with flush base connection improves water flow. These features not only create a sturdy anchorage to the

FCS II Surfboard Fin Boxes 0 o  3o  5o  9 o

Efficient keyless system for quick fin installation and release. The FCS II system requires no grub screws or keys to secure the fins to the board. Fins can be easily inserted and removed in seconds, allowing you to adapt your equipment to the conditions, on land and in the water. Recessed leading edge with flush base connection improves water flow. These features not only create a sturdy anchorage to the board, but minimize water disruption through a more flush and seamless transition between the fin and board surface.

The FCS II System is backwards compatible with all your favorite FCS dual tab Fins. Constructed using a corrosion resistant titanium tension rod, and a rotating, wear-resistant polymer barrel.  When the fin is inserted into the plug the barrel interacts with a groove detail in the fin to lock it into place using a combination of downward and lateral force.

Lightweight Composite Frame encapsulated by high density foam reduces weight and maintains flex.

  • Center - 1 plug (Box) only
  • Side Set - 2 plugs (Boxes) (left and right - only sold as a pair no singles)
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 40938628003

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4.8 ★★★★★
Based on 27 reviews
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PETER CROWE
Fort Morgan, US
★★★★★ 5
Great for walking all day at work as well
Size: X-Large, Color: (001) Black / Black / White
I walk approximately 10 miles a day at work, in a manufacturing setting. On concrete with steel toe shoes. My feet have been begging me to change from the socks that I have worn for years. I have worn these other name brand socks for probably 10 years. So, change was obviously something I had to be pushed into. I got on Amazon and searched for training socks. I read the description. Glanced at the reviews. I decided to move forward with purchasing these. I could not have been happier. My feet began feeling better immediately. And the priced was very reasonible.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 12, 2026
J
Verified Purchase
jcolis
Lowell, US
★★★★★ 5
You have one pair of feet. Treat them kindly with a pair of UA socks
Size: Large, Color: (100) White / White / Black
Soft and tough. Easy on the feet. Nice fit prevents sore spots and blisters.
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Reviewed in the United States on December 3, 2025
L
Verified Purchase
LC
Belleville, US
★★★★★ 5
LOVE THEM!!
Size: Small, Color: (001) Black / Black / Castlerock
LOVE! These socks are so comfortable! I wear a 5 in women's and a 3 in big kid shoes. The small fit me perfectly. I see where some say they run small but I can't say that was an issue for me. They are "snug" but thats what you want with a no show sock. I feel they have support vs the ones i used to buy at Walmart. They are very soft! I am actually buying more today and throwing my other ones in the trash!
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Reviewed in the United States on February 18, 2026
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Verified Purchase
Lucy Mejia
Natrona Heights, US
★★★★★ 5
So will not write down your foot
Size: Medium, Color: (001) Black / Black / Castlerock
I love these socks. They have a little bit of gel on the top of the heel for support in your tennis shoes and so your socks don’t write down. Very good quality.
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Reviewed in the United States on May 6, 2026
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Twins9
San Leandro, US
★★★★★ 5
Comfy and Stay Put
Size: Medium, Color: (002) Black / Black / Halo Gray
These socks are honestly great. They’re super thin and light, so once you have them on, you kind of forget they’re even there. No bulky feeling in your shoes at all. The best part is they actually stay on. I hate no-show socks that slide down after five minutes, and these don’t do that. The little grip on the heel really works, so you’re not constantly adjusting them all day. They’re breathable too, which is nice if your feet run warm. They dry fast and don’t get that gross sweaty feeling. And there’s no annoying seam on the toe, so nothing rubs or feels uncomfortable. Basically, they’re just comfy, stay put, and don’t cause problems — which is all I want from socks.
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Reviewed in the United States on January 16, 2026

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