Introduction
This manual provides comprehensive instructions for the safe and effective use of your Milwaukee Redlithium USB Stick Light, Model 2128-21. Please read this manual thoroughly before operating the device and retain it for future reference. This light is designed for general tasks and inspection work, offering versatile lighting solutions in various environments.

Figure 1: Milwaukee Redlithium USB Stick Light and included USB-C cable.
Product Overview
The Milwaukee Redlithium USB Stick Light is a compact and durable lighting tool featuring a slim light blade design. It provides high-definition output and multiple lighting modes for various applications. Key features include:
- High-Definition Output: Delivers up to 550 lumens for clear visibility.
- Adjustable Light Head: Features 220° of vertical rotation for precise light positioning.
- Multiple Lighting Modes: Offers four distinct modes: inspection, front panel, back panel, and dual panel (both front and back).
- Brightness Options: Two brightness settings (High/Low) to manage output and extend run-time.
- Versatile Mounting: Equipped with a strong magnetic base and an integrated hook for hands-free operation and limitless mounting positions.
- USB-C Rechargeable: Integrated USB-C port for convenient and quick charging.
- Durable Construction: IP54 rated for dust and water resistance, impact resistant up to 6 feet, and corrosion-resistant to common chemicals.
- Swappable Battery: Utilizes a REDLITHIUM USB 3.0 battery, allowing for quick swaps to minimize downtime.

Figure 2: Key features and utility of the Milwaukee Redlithium USB Stick Light.
Video 1: Demonstration of the Milwaukee Redlithium USB Stick Light's features, including its adjustable head, magnetic base, and various lighting modes.
Setup
Battery Installation and Charging
The Milwaukee Redlithium USB Stick Light uses a REDLITHIUM USB 3.0 battery. Ensure the battery is properly installed and charged before first use.
- Install Battery: To install or replace the battery, twist the bottom cap of the light counter-clockwise to remove it. Insert the REDLITHIUM USB 3.0 battery into the compartment with the correct orientation. Replace the bottom cap by twisting it clockwise until secure.
- Charge Battery: Open the rubber cover on the side of the light to reveal the USB-C charging port. Connect the provided USB-C cable to the light and to a compatible USB power source (e.g., wall adapter, computer USB port).
- Charging Indicator: The power button will illuminate to indicate the charging status. Refer to the 'Battery Status Indicator' section for details on light patterns.

Figure 3: Components included with the Milwaukee Redlithium USB Stick Light.
Operating Instructions
Power On/Off and Brightness Adjustment
- Power On/Off: Press the main power button to turn the light on or off.
- Brightness Adjustment: While the light is on, press the intensity button (located above the power button) to cycle between High and Low brightness settings.
Lighting Mode Selection
The light features a mode button to switch between different lighting configurations:
- Front Panel: Illuminates the main light panel.
- Back Panel: Illuminates the rear light panel.
- Dual Panel: Illuminates both front and back panels simultaneously.
- Inspection Light: Activates the focused light at the tip for detailed inspection.
Press the mode button repeatedly to cycle through these options.
Adjusting the Light Head
The light head can be rotated up to 220° vertically. Gently pivot the light head to direct illumination precisely where needed.
Mounting Options
- Magnetic Base: The strong magnetic base allows the light to be securely attached to metallic surfaces for hands-free operation.
- Integrated Hook: A retractable hook is located at the base, providing an additional option for hanging the light in various work environments.
Video 2: Overview of the Milwaukee Redlithium USB Stick Light's functionality, including its multiple light modes and magnetic mounting capabilities.
Video 3: Demonstration of the light's compact design, brightness, and various features for practical use.
Maintenance
Cleaning
To maintain optimal performance and extend the lifespan of your Milwaukee Redlithium USB Stick Light, follow these cleaning guidelines:
- Regularly clean dust and debris from the light's vents and surfaces.
- Use only mild soap and a damp cloth for cleaning. Avoid using harsh solvents or chemicals, as these can damage plastic components and seals.
- Ensure the USB-C port cover is securely closed when not charging to prevent dust and water ingress.
Storage
Store the light in a cool, dry place away from direct sunlight and extreme temperatures. If storing for extended periods, ensure the battery is partially charged (around 50%) to preserve battery health.
Troubleshooting
If you encounter issues with your Milwaukee Redlithium USB Stick Light, refer to the following common troubleshooting steps:
- Light Not Turning On: Check if the battery is properly installed and charged. If the battery indicator shows low charge, recharge the battery.
- Dim Light Output: Ensure the light is not in a low brightness setting. Press the intensity button to switch to high brightness. If the issue persists, the battery may be low.
- Charging Issues: Verify that the USB-C cable is securely connected to both the light and the power source. Try using a different USB-C cable or power adapter to rule out cable/adapter malfunction.
- Intermittent Operation: Ensure the battery is fully seated and the cap is tightened. Check for any visible damage to the light or battery.
For persistent issues not resolved by these steps, please contact Milwaukee customer support.
Specifications
| Feature | Specification |
|---|---|
| Brand | Milwaukee |
| Model Number | 2128-21 |
| Power Source | Cordless (REDLITHIUM USB 3.0 Battery) |
| Voltage | 4 Volts (DC) |
| Luminous Flux | 550 Lumens |
| Light Type | LED |
| Rotation Angle | 220° Vertical |
| Ingress Protection (IP) Rating | IP54 (Dust & Water Resistant) |
| Impact Resistance | Up to 6 feet |
| Material | Aluminum |
| Item Weight | 16 ounces (1 pound) |
| Package Dimensions | 11.89 x 5.2 x 2.24 inches |

Figure 4: Run-time specifications for various lighting modes and brightness settings.
Warranty and Support
The Milwaukee Redlithium USB Stick Light (Model 2128-21) is backed by a limited lifetime warranty. For warranty claims, technical support, or service inquiries, please contact Milwaukee Electric Tool customer service or visit their official website. Keep your purchase receipt as proof of purchase.
Manufacturer: MILWAUKEE ELECTRIC TOOL





