1. Introduction
This manual provides detailed instructions for the assembly, operation, and maintenance of your Ergotron LX Vertical Stacking Dual Monitor Arm. Please read these instructions carefully before installation and use to ensure proper function and safety. This product is designed to enhance your workspace ergonomics by allowing flexible positioning of two monitors.
2. Package Contents
Verify that all components listed below are present in your package. If any parts are missing or damaged, please contact Ergotron customer support.
- Two (2) LX Arms and Extensions
- One (1) 23-inch Pole
- One (1) Heavy-duty Two-piece Desk Clamp (for surfaces 0.63 to 2.6 inches thick)
- One (1) Grommet Mount Plate and Hardware (for installation through a desktop hole)
- Two (2) Pole Collars
- Two (2) Caps
- Mounting Hardware (screws, washers, tools)

Image: All components included in the Ergotron LX Vertical Stacking Dual Monitor Arm package.
3. Specifications
| Model Number | 45-509-216 |
| Brand | Ergotron |
| Color | White |
| Material | Metal |
| Mounting Type | Tabletop Mount (Clamp or Grommet) |
| Movement Type | Articulating |
| Monitor Compatibility | Two (2) screens up to 40 inches each |
| Weight Capacity | 7 to 22 lbs (3.2 to 10 kg) per monitor |
| VESA Compatibility | 75x75mm, 100x100mm |
| Vertical Lift | 13 inches (33 cm) |
| Rotation | 360 degrees |
| Tilt Range | 75 degrees |
| Product Dimensions | 30.3 x 17.7 x 7.1 inches (77 x 45 x 18 cm) |
| Item Weight | 19 pounds (8.6 kg) |
| UPC | 698833061581 |
4. Setup and Installation
Follow these steps to properly install your Ergotron LX Vertical Stacking Dual Monitor Arm.
4.1 Choose Your Mounting Option
The LX arm supports two primary mounting methods: desk clamp or grommet mount. Select the option best suited for your desk.
- Desk Clamp: Suitable for desk edges 0.63 to 2.6 inches (1.5 to 6.6 cm) thick.
- Grommet Mount: Requires a desktop hole between 0.3 and 2 inches (0.8 to 5 cm) in diameter, with a maximum desk thickness of 3 inches (7.6 cm).

Image: Desk clamp and grommet mount options with specified desk thickness requirements.
4.2 Assembly Steps
- Attach the Pole: Secure the 23-inch pole to your desk using either the desk clamp or grommet mount hardware. Ensure it is tightened firmly to prevent movement.
- Install LX Arms: Slide the LX arms onto the pole at your desired vertical positions. Use the pole collars to fix their height.
- Attach VESA Plates to Monitors: Secure the VESA mounting plates to the back of your monitors using the provided screws. Ensure the screws are appropriate for your monitor's VESA pattern (75x75mm or 100x100mm).
- Mount Monitors: Carefully lift each monitor and slide its VESA plate onto the corresponding LX arm's mounting head. Secure with the locking mechanism.
- Adjust Tension: The arms are pre-tensioned, but you may need to adjust the tension to match the weight of your monitors. Use the included hex key to turn the tension screw on each arm until the monitor holds its position without drifting up or down.
5. Operation and Adjustment
The Ergotron LX arm offers extensive adjustability to optimize your viewing experience.
5.1 Monitor Positioning
- Vertical Stacking: Position monitors one above the other for a vertical dual-screen setup. The 23-inch pole allows for significant vertical separation.
- Side-by-Side: Arrange monitors horizontally next to each other.
- Height Adjustment: The arms provide 13 inches (33 cm) of vertical lift, allowing monitors to rise up to 31.7 inches (80.5 cm) from the desktop.
- Tilt: Adjust the monitor tilt up to 75 degrees to reduce glare and optimize viewing angles.
- Pan and Rotation: Each monitor can be rotated 360 degrees for portrait or landscape orientation and panned left or right independently.

Image: Illustrates the range of motion for the LX arm, including tilt, pan, and rotation capabilities.
5.2 Cable Management
Integrated cable management channels help keep your workspace tidy. Route monitor cables through the designated clips along the arms and down the pole to maintain a clean aesthetic and prevent cable clutter.

Image: Example of proper cable routing through the integrated management system.
6. Maintenance
Regular maintenance ensures the longevity and optimal performance of your monitor arm.
- Cleaning: Wipe the arm surfaces with a soft, damp cloth. Avoid abrasive cleaners or solvents.
- Check Connections: Periodically inspect all screws and mounting points to ensure they remain tight and secure. Re-tighten if necessary.
- Tension Adjustment: If monitors begin to sag or become difficult to move, re-adjust the arm tension as described in the setup section.
7. Troubleshooting
Refer to the following common issues and solutions before contacting customer support.
- Monitor Sags or Drifts:
Solution: The arm tension may be too low for the monitor's weight. Use the provided hex key to increase the tension on the arm's adjustment screw. Turn clockwise to increase tension. - Monitor is Difficult to Move:
Solution: The arm tension may be too high. Use the provided hex key to decrease the tension on the arm's adjustment screw. Turn counter-clockwise to decrease tension. - Arm Feels Unstable:
Solution: Ensure the desk clamp or grommet mount is securely fastened to the desk. Check that all pole and arm connections are tight. If using a desk clamp on a particle board or thin desk, consider using a reinforcement plate (not included) to distribute the pressure. - Monitors Not Aligned:
Solution: Adjust the individual monitor tilt, pan, and rotation at the VESA head to achieve desired alignment. Ensure both arms are set at the same height on the pole if a level horizontal arrangement is desired.
8. Warranty Information
Ergotron products are designed for durability and undergo extensive quality testing. The Ergotron LX Vertical Stacking Dual Monitor Arm comes with a 10-year warranty. This warranty covers defects in materials and workmanship under normal use. Please retain your proof of purchase for warranty claims.
For specific warranty terms and conditions, please refer to the official Ergotron website or contact customer support.
9. Customer Support
If you encounter any issues not covered in this manual or require further assistance, please contact Ergotron customer support.
- Website: Visit the official Ergotron website for FAQs, product registration, and additional resources.
- Contact: Refer to the Ergotron website for current contact information, including phone numbers and email support.





