FPN All-Aluminum Extension Double Socket Arm, Adjustable Telescopic Mounting Arm 11.5 to 17 Inch
Quick take
This telescopic double socket arm extends from 11.5 to 17 inches, built for 1-inch (25mm) ball mounting systems like RAM B-size. Buyers tend to like the smooth extension and the stability once locked, especially for GPS, radios, and marine or off-road setups. The main caveat is ensuring the locking hardware stays tight for your specific mounting location, since a few buyers report looseness or surface abrasion from the adjustment hardware.
Pros and cons
Pros
- 2-stage telescopic design adjusts reach from 11.5 to 17 inches for better sightlines
- Dual 1-inch (25mm) ball sockets with 360° rotation at both ends for flexible aiming
- All-aluminum, CNC-machined arm with hard anodized finish for corrosion resistance
- Reviewers report the slide feels smooth and the arm stays put when properly locked
Cons
- Locking the adjustment/length can require extra torque, and some buyers mention looseness over time
- Grip surfaces on adjustment hardware can be abrasive and may scuff nearby dashboards or surfaces
- Less suitable for lightweight mounting points that cannot handle the extra leverage of an extended arm
What buyers think
Buyer-review evidence is mixed but generally points to strong mechanical performance when tightened correctly. Several reviewers highlight a smooth telescoping slide, good grip, and solid stability once locked. A smaller number of buyers report two main issues: the length-lock hardware can come loose, and the abrasive nature of the adjustment grip can scratch a dashboard or other nearby surfaces. One negative report suggests that the arm’s added weight and leverage may be too much for certain clamp-based mounting scenarios (for example, supporting heavier loads on a steering-column style clamp). Overall, the pattern suggests this is a quality arm for the right ball-mount setup, but it needs careful tightening and thoughtful placement to avoid scuffs and vibration-related loosening.
Key features that matter in real-world use
Telescoping reach from 11.5 to 17 inches
The 2-stage telescopic design lets you extend or retract the arm to bring devices closer for visibility, reduce glare, or improve accessibility. That adjustability is especially useful when you are trying to adapt an existing vehicle or marine setup without redesigning the whole mount geometry.
Dual 1-inch ball sockets with full 360° rotation
Both ends use a standard 1-inch (25mm) ball socket, with 360° rotation capability. In practice, that means you can dial in orientation for different device types, such as a GPS for easy line-of-sight or a radio for more comfortable viewing and operation.
All-aluminum, hard anodized for corrosion resistance
The arm is made from aerospace-grade aluminum and finished with a hard anodized surface intended to resist corrosion. That matters for boats, outdoor work vehicles, and any environment with saltwater spray or regular UV exposure.
Compatibility with RAM B-size and 25mm ball components
It is designed to work with RAM B-size mounts and other industry-standard 1-inch (25mm) ball components. This is what makes it a practical upgrade accessory when your system already uses that ball diameter.
Pros and cons, translated into buying advice
When this telescopic double socket arm is a smart choice
- You want adjustable reach (11.5 to 17 inches) to improve sightlines on a dash, marine console, or workstation
- Your existing setup uses RAM B-size mounts or 1-inch (25mm) ball components and you want to extend it without switching systems
- You care about corrosion-resistant construction for outdoor use
- You are mounting lighter gear where you can secure both ends and lock the joints firmly
When you should think twice
- Your mounting point is a flexible clamp or support that might not handle the added leverage from an extended arm
- You are mounting near surfaces that scratch easily, since the adjustment hardware grip can be abrasive
- You need a “set it and forget it” solution without re-checking tightness after vibration, because some buyers report looseness with the lock screw (your tightening technique and setup will matter)
Price and availability
At the time of writing, the listed price is $29.99 USD (with a higher list price shown). Availability is shown as in stock. If you are comparing options, consider not just the arm itself, but also whether you already own compatible 1-inch (25mm) ball components and the exact mounting base you plan to attach to.
Verdict
The FPN all-aluminum extension double socket arm is a strong fit for anyone building or upgrading a RAM B-size (1-inch ball) mounting system and needing a longer, adjustable reach with flexible aiming. Buyers commonly describe smooth extension and stable performance once locked, and the aluminum, anodized construction suits outdoor and marine conditions. Just be sure your mounting base can handle the leverage of an extended arm, and take care around dashboards or other scratch-prone surfaces. If those points match your use case, it can be a practical way to dial in device placement.
FAQs
Will this arm work with RAM mounts?
It is compatible with RAM B-size mounts and other industry-standard 1-inch (25mm) ball components, as those use the same ball diameter.
How far does the telescopic arm extend?
The arm adjusts using a 2-stage telescopic design, extending from 11.5 inches to 17 inches.
Does it allow adjustment on both ends?
Yes. It uses dual 1-inch ball sockets, allowing 360° rotation at both ends, so you can independently aim both connection points.
Is it suitable for marine or outdoor use?
The arm is made from aluminum with a hard anodized finish intended for corrosion resistance, which can make it a better match for harsh outdoor environments.
What is the main drawback buyers mention?
The most commonly surfaced concerns are the lock hardware needing enough torque to stay secure and the possibility that abrasive grip surfaces can scuff or scratch nearby surfaces if they rub.
Specifications
| Product Title | All-Aluminum Extension Double Socket Arm, Adjustable Telescopic Mounting Arm 11.5 to 17 Inch, Compatible with RAM B Size Mounts and Other Industry Standard 1" / 25mm Ball Components |
|---|---|
| Category | Electronics > GPS, Finders & Accessories > GPS System Accessories > Vehicle Mounts |
| Brand | FPN |
| Manufacturer | FPN |
| Model Name | FBM-129 |
| Model Number | FBM-129 |
| Color | Black |
| Compatible Devices | B Size 1" Ball Components |
| Compatible Phone Models | RAM Mounts |
| Mounting Type | 1" Ball Mount |
| Additional Features | Adjustable, Rotatable |
| Compatible with Vehicle Type | Boat, Truck |
| Unit Count | 1.0 Count |
| Enclosure Material | Aluminum |
| UPC | 717325337307 |
| Warranty Description | 1 |
| Built-In Media | FBM-129 |
Available variants
Size
- 8.6 to 11.3"
- 11.5 to 17"
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