Adapter Guide
This guide will help you find the right adapter, step by step.
The right adapter for your e-Fin on the fin box used on your SUP board. Since es are es systems and designs, es ’s not always possible to determine the correct one at a glance. However, you can often identify the right fin box by checking the exact model of your board. It’s best to look up the manufacturer’s description of your SUP and pay attention to terms like “slide-in,” “US box,” or Smart Lock.”
HOW IS YOUR FIN ATTACHED?
es are basically es systems. Click on the category that matches your board and follow the corresponding instructions.
a. PIN systems
Pin systems are designed to be particularly simple. The fin is inserted and then secured with a pin. This system is quick, reliable, and requires no tools.
Typical features of pin systems:
• no screw mechanism
• no lever or click system
• secured by a separate or integrated pin
Slide-in adapter
The slide-in adapter uses a tool-free plug-in system with a pin lock. The fin is inserted into the adapter from the back and then secured by an integrated pin.
Dimensions (approx.):
• Length: 177.66 mm
• Width: 34.34 mm
Typical use:
• Primarily for inflatable SUPs in the beginner and recreational segments
• Commonly found on budget to mid-range boards
• Used by brands such as Aqua Marina and many retail and private labels
How to identify a slide-in fin at home: The fin is simply slid in and secured with a small pin. Es no lever or click mechanism. If a separate pin needs to be inserted or pushed through, es usually a slide-in system.
ITIWIT Adapter
The ITIWIT adapter is also based on a pin system, but is specifically designed for the fin boxes on Decathlon (ITIWIT) boards. It works similarly to the classic slide-in system, but the geometry differs slightly.
Dimensions (approx.):
• Length: 168.52 mm
• Width: 33.42 mm
Typical use:
• Specially designed for Decathlon SUPs of the ITIWIT brand
• Commonly found on entry-level and all-round boards from this brand
How to identify ITIWIT at home: Visually similar to the Slide-In system, but the adapter fits only precisely into ITIWIT fin boxes. If the board is from Decathlon (ITIWIT) and uses a pin system, es most likely the adapter in es .
Aquatone Adapter
The Aquatone adapter uses a tool-free pin or push-in system. The fin is inserted from the back and then locks securely into the designated mount.
Typical use:
• For Aquatone SUP boards
• Common on entry-level and all-round boards from this brand
How to identify Aquatone at home: The fin is inserted and secured without screws. A typical feature is the special base with notches or guides—it usually fits only on Aquatone boards.
b. Screw (traditional US speaker systems)
Screw-on systems are among the classic mounting methods in the SUP sector and are primarily used with US box systems. The fin or adapter is inserted into the fin box and then secured with a screw.
Typical of classic US box systems:
• Mounted using a single screw
• Commonly found on rigid and inflatable SUP boards
• Sturdy and secure connection between the adapter and the board
US Box Adapter
The US Box Adapter is the standard solution for classic US Box fin boxes. It conforms to the standard geometry used on many SUP boards and serves as a reference model for comparison with alternative designs such as the Modified US Box or Reversed US Box.
Dimensions (approx.):
• Length: 180 mm
• Height: 24 mm
Typical use:
• For standard US-Box fin boxes
• Suitable for split and non-split US-Box systems
How to identify the US-Box at home: The US-Box is the classic screw-in system in the SUP sector. If your fin or adapter is secured with a screw and does not have a brand-specific special shape, es usually a standard US box. Standard geometry with a normally positioned guide pin. The guide pin is located at approx. 13.5 mm and thus engages at the usual point in the fin box.
Modified US Box Adapter (Starboard)
The Modified US Box Adapter is designed for fin boxes with a different US box geometry. Visually, it closely resembles the standard US Box Adapter, but differs in key details regarding fit. As a result, it is not compatible with a standard US box.
Dimensions (approx.):
• Length: 181 mm
• Height: 24 mm
Typical use:
• For Modified US Box systems
• Particularly relevant for Starboard Deluxe models with adapted box geometry
How to identify the Modified US Box at home: From the outside, the Modified US Box often looks almost identical to the standard US Box. The key difference lies in the position of the guide pin: On the Modified US box, it is located at approximately 17.5 mm instead of approximately 13.5 mm. As a result, the adapter engages at a different point in the fin box.
Difference between the
, US Box, and Modified US Box
The Standard US Box and the Modified US Box look very similar, but differ in one important detail:
the position of the guide pin.
On the standard US box, the guide pin is located at approximately 13.5 mm, while on the modified US box , it is located at approximately 17.5 mm. As a result, the adapter engages at a different point in the fin box. Even though both versions look nearly identical at first glance, they are therefore not compatible with each other.
Important:
• For boards with a standard US box, the standard US box adapter
is required
• For certain Starboard boards with a modified box, the modified
US box adapter is required
Reversed-
-to-US Box Adapter (Aztron)
The Reversed US Box Adapter is designed for fin boxes with a reversed or mirrored US box geometry. Compared to the other two versions, this adapter is significantly more compact and has a distinctly different shape.
Dimensions (approx.):
• Length: 139 mm
• Height: 22 mm
Typical use:• For Reversed US Box systems• Common on Aztron boards• For fin boxes with reversed geometry
How to identify a Reversed US Box at home: If the adapter area appears significantly shorter or the mounting positions do not match those of a classic US Box, es may es a Reversed US Box. As a result, this adapter is not interchangeable with either the Standard US Box or the Modified US Box.
c. Click/lever mechanism
(tool-free click systems)
Click and lever systems allow for tool-free installation of the fin. The fin is inserted and either snaps into place immediately or is additionally locked in position using a lever mechanism. These systems are specifically designed for quick and easy handling.
Typical features of click/lever mechanisms:
• tool-free installation
• snap-in or active locking of the fin
• quick and easy handling
Smartlock Adapter
The Smartlock adapter features a tool-free click or lever mechanism. The fin is inserted and securely locked in place by a visible locking mechanism. The system is designed for quick and easy use and is one of the most widely used click systems in the SUP sector.
Dimensions:
• Length: 157.28 mm
• Height: 19.1 mm
Special feature: More compact and slightly shorter than Swift Attach.
How to recognize Smartlock at home: More compact and slightly shorter than Swift Attach. The fin is inserted and then actively locked into place. If a part needs to be moved, pressed, or flipped during insertion, es usually a Smartlock system.
Swift Attach Adapter
The Swift Attach adapter also uses a tool-free click system. The fin is guided into place and snaps securely into position. This makes installation particularly quick and easy. Compared to Smartlock, this system is somewhat less common, but is also used on certain SUP models.
Dimensions:
• Length: 165.5 mm
• Height: 21.5 mm
How to identify Swift Attach at home: Longer than Smartlock. The Swift Attach system es traditional visible lever. The fin is simply inserted and clicks into place immediately. If nothing needs to be flipped or locked during insertion and the fin snaps into place directly, es usually Swift Attach.
Difference between the
Smartlock Adapter and the Swift Attach Adapter
Bestway Adapter
The Bestway adapter also uses a tool-free click system and works similarly to a classic slide-in system. The fin is inserted and then secured by a click mechanism.
Typical use:
• For Bestway SUP boards
• Common on beginner and recreational SUPs
How to recognize Bestway at home: Click system without screws or levers. The adapter is usually longer and flatter in design and does not fit neatly into classic slide-in systems or other plug-in systems.
d. Retrofit solution:
(no fin box available)
A fin box is not always available. For such applications, es is es solution that allows the e-Fin to be installed e-Fin without an existing fin box system.
adhesive dock
The adhesive dock is a retrofit solution for applications without an existing fin box. Es adhered to the surface, providing the foundation for e-Fin mounting the e-Fin . Unlike the other adapters, es not a solution for existing fin boxes, but rather a standalone system for retrofitting.
Typical uses:
• when no fin box is available
• for retrofitting SUPs without a fin box
• for equipping other water sports products with e-Fin
Special feature: Stand-alone adhesive solution—independent of existing fin box systems.
