1. Introduction
This manual provides detailed instructions for the proper installation, operation, and maintenance of your Sigma Hiro LED Rear Bicycle Light, model 19100. Please read this manual thoroughly before using the product to ensure safe and efficient operation. Retain this manual for future reference.
2. Product Features
- High Power Red LED: Provides bright and clear rear illumination for enhanced visibility.
- Visibility: Offers visibility up to 300 meters.
- Two-Stage Battery Indicator: Alerts you to the battery status.
- Extended Operating Time: Up to 60 hours of continuous operation.
- Easy Battery Change: Designed for simple replacement of 2 x Size N (LR1) batteries.
- Tool-Free Mounting: Quick and straightforward installation without the need for tools.
- Waterproof Design: Rated IPX4 for resistance against splashing water from any direction.
3. Package Contents
Please verify that all items are present in the package:
- Sigma Hiro LED Rear Bicycle Light (Model 19100)
- Bicycle Mounting Bracket
- 2 x Size N (LR1) Batteries
4. Setup and Installation
4.1. Inserting Batteries
- Locate the battery compartment cover on the rear light.
- Open the cover by gently prying it open or sliding it as indicated on the device.
- Insert the two Size N (LR1) batteries, ensuring correct polarity (+/-) as marked inside the compartment.
- Close the battery compartment cover securely to maintain the waterproof seal.
4.2. Mounting the Light
The Sigma Hiro LED Rear Bicycle Light features a tool-free quick mounting system.
- Attach the mounting bracket to your bicycle's seat post or rear frame. Ensure it is positioned vertically and securely tightened.
- Slide the Sigma Hiro light onto the mounting bracket until it clicks into place.
- Verify that the light is firmly attached and facing directly backward for optimal visibility.

Image 1: Sigma Hiro LED Rear Bicycle Light and its mounting bracket shown on packaging, illustrating the components for installation.
5. Operation
To operate the Sigma Hiro LED Rear Bicycle Light:
- Turning On/Off: Press the button located on the top of the light to turn it on or off.
- Light Mode: The light operates in a single, continuous illumination mode. There are no flashing modes available.

Image 2: The Sigma Hiro LED Rear Bicycle Light, showcasing its compact black casing, prominent red LED, and the white power button on top.
6. Battery Information and Maintenance
6.1. Battery Indicator
The integrated two-stage battery indicator will signal when the batteries are running low, prompting replacement to maintain optimal light performance.
6.2. Battery Replacement
When the battery indicator signals low power or the light dims, replace both Size N (LR1) batteries following the steps in Section 4.1. Always use new batteries of the specified type.
6.3. Water Resistance
The Sigma Hiro light is waterproof with an IPX4 rating, meaning it is protected against splashing water. Ensure the battery compartment cover is always securely closed to maintain this protection.
6.4. Cleaning
Clean the light's casing and lens with a soft, damp cloth. Do not use abrasive cleaners or solvents, as these may damage the product.
7. Troubleshooting
- Light does not turn on:
- Check if the batteries are inserted correctly with the right polarity.
- Replace the batteries with new ones.
- Light is dim:
- The batteries are likely low. Replace them with new ones.
- Light is not securely mounted:
- Ensure the mounting bracket is firmly attached to the bicycle and the light is clicked into the bracket.
8. Specifications
| Model Number | 19100 |
| Light Source | 1 High Power Red LED |
| Battery Type | 2 x Size N (LR1) |
| Operating Time | Up to 60 hours |
| Visibility | 300 meters |
| Water Resistance | IPX4 (Splash-proof) |
| Weight | Approximately 99.79 grams |
| Mounting | Tool-free quick mounting |

Image 3: Packaging of the Sigma Hiro LED Rear Bicycle Light, displaying key features and specifications in multiple languages.
9. Safety Information
- Always ensure the light is securely mounted before riding.
- Do not look directly into the LED, as it may cause temporary vision impairment.
- Keep batteries out of reach of children.
- Dispose of used batteries according to local regulations.
- This light is intended to increase your visibility to others; it does not replace the need for safe cycling practices.
10. Warranty and Support
For warranty information, technical support, or service inquiries, please refer to the official Sigma Sport website or contact your authorized retailer. Please have your product model number (19100) and proof of purchase available when contacting support.







