They are 3mm thick for use with an 8mm bolt. Chassis panel tabs. Tabs are cut to 8.25mm to give clearance on the bolt. The offset version has been produced for use in corners.
eBay
AQUBONA Fiberglass Honeycomb Surfboard Fin Thruster Surf Fin or Quad Set Single Tab or Dual Tab S/M/L Size With Key and Screws
Aliexpress UK
We also have these tabs in 3mm thick.
eBay
Dual Tab II Medium Performer Fiberglass Reinforced Polymer Surfboard Fins 2/3/4/5 Fins Thruster (3 Fins) Dual Tab Blue Black
Aliexpress UK
(Rivet on versions soon available). Tired of building your race cars and wanting a tidy, lightweight solution to wiring routing?.
eBay
AQUBONA Surfboard Fins Honeycomb Fiberglass Performance Twin,Thruster (3 Fins) Quad 5 Fins Single Tab or Twin Tab Size
Aliexpress UK
8mm thick mild steel tab 16mm hole approx 45mm up from base THIS IS FOR 2 PIECES
eBay
Twin Keel Fins (2 Fins) - Twin Tab or Single Tab Sizes, with Fin Screws and Fin Key - Fins for Fish Surf Boards
Aliexpress UK
We have made our own tooling which allows us to fit the shortest length nutsert in a 3mm thick bracket. Therefore these brackets are only supplied with nutserts already fitted. Tabs are 3mm thick. Chassis panel tabs with nutserts.
eBay
Surfboard Tri Fins Set, Honeycomb Fiberglass Performance, Compatible with Single Tab or Twin Tab, Multiple Colour, M and L Size
Aliexpress UK
They are 4mm thick for use with an 8mm bolt. Chassis panel tabs.
eBay
Spot Welding Pen Plier Wrench Wire Kit Adjustable Repairing Spot Welding Machine Butt Soldering Tong Tools 18650 Spot Weld
Aliexpress UK
To Suit 16mm Gate Pin.
eBay
Tri Fin Set UPSURF FCS Fins S/M/L Surf Fins Honeycomb Surfboard Fin Thruster Kayak Stabilizer Multicolor Double Tabs 1 Fins
Aliexpress UK
Weld On Tab. 20mm hole, 95mm up from base. 4 x Laser cut steel brackets.
eBay
Floating Swimming Pool Chemical Floater Chlorine Bromine Tablets Floating Dispenser Applicator Swimming Spa Hot Tub Supplies
Aliexpress UK