COSLUS C51
COSLUS C51 Portable Dental Water Flosser: User Manual
Model: C51
1. Product Overview
The COSLUS C51 Portable Dental Water Flosser is designed for effective and convenient oral hygiene. It features multiple modes and adjustable pressure settings to cater to various dental needs, including daily cleaning, orthodontic care, and sensitive gums. Its portable design and waterproof rating make it suitable for both home and travel use.
Key Features:
- 3 Modes & 18 Adjustable Pressure Settings: Offers 3 modes (Clean, Orthodontic, Jet) each with 6 settings, providing 1400-1800 pulses and 30-140 PSI water pressure.
- Unique Dual-Stream Water Technology: Utilizes an advanced ultra-fine 0.3mm + 0.3mm dual-thread water pulse technology for effective plaque removal and deep cleaning.
- 30-Day Battery Life & Portable: Equipped with a large rechargeable battery providing up to 30 days of use after a 2-hour charge. Lightweight and compact for travel.
- IPX7 Removable Large Capacity Tank: Features a 300ml removable tank for easy refilling and cleaning. IPX7 waterproof for safe use in showers.
- Multi-function Nozzles: Includes 2 standard nozzles, 1 orthodontic nozzle, and 1 periodontal pocket nozzle for comprehensive 360° cleaning.
- Charging Port Update: Product may come with either a USB-A or Type-C charging cable. Adapter is not included.

Figure 1: COSLUS C51 Portable Dental Water Flosser and included nozzles.

Figure 2: The IPX7 waterproof design allows for safe use in the shower.
2. Setup
2.1 Charging the Device
Before first use, fully charge the device. The COSLUS C51 may come with either a USB-A or Type-C charging cable. Please verify your charging port type. An adapter is not included; use any 5V adapter.

Figure 3: Charging port options (Type-C or USB-A). Please check your device.
2.2 Attaching a Nozzle
- Select the desired nozzle (standard, orthodontic, or periodontal).
- Insert the nozzle into the opening at the top of the device until it clicks securely into place. Ensure there is no gap between the nozzle and the device.
- The nozzle can rotate 360 degrees for optimal cleaning angles.
Video 1: Demonstration of attaching and rotating the nozzle. This video illustrates how to correctly insert the nozzle until it clicks and shows its 360-degree rotation capability.

Figure 4: Visual guide for initial setup and usage steps.
2.3 Filling the Water Tank
The COSLUS C51 features a 300ml removable water tank with an extra-wide opening for easy filling and cleaning. To fill:
- Detach the water tank from the main unit by twisting or pulling it down (refer to device specific mechanism).
- Fill the tank with lukewarm water. You may add mouthwash if desired, but ensure it is non-alcoholic and diluted as per mouthwash instructions.
- Reattach the water tank to the main unit, ensuring it is securely fastened to prevent leaks.

Figure 5: The COSLUS C51's wide-mouth, removable water tank for easy filling and cleaning.

Figure 6: The compact design makes the COSLUS C51 ideal for travel.
3. Operating Instructions
3.1 Selecting a Mode and Pressure Level
The COSLUS C51 offers 3 cleaning modes, each with 6 adjustable pressure settings, totaling 18 intensity levels. To select:
- Clean Mode: For daily plaque removal and general cleaning.
- Orthodontic Mode: Specifically designed for cleaning around braces and orthodontic appliances.
- Jet Mode: For precise, targeted cleaning and stain removal. This mode features an anti-splash design.
Press the "Mode" button to cycle through the available modes. Once a mode is selected, use the pressure adjustment button to choose your desired intensity level (1-6). The device is designed to cover users from 6 to 70 years old, with lower settings for children and sensitive users, and higher settings for deep cleaning.

Figure 7: Mode and pressure level selection for personalized cleaning.

Figure 8: The improved Jet mode for precise, splash-free flossing.
3.2 Proper Usage Technique
For optimal results, follow these steps:
- Lean over a sink and place the nozzle tip in your mouth.
- Aim the water stream at a 90-degree angle to your gumline.
- Turn on the device using the ON/OFF button.
- Move the nozzle along your gumline, pausing briefly between teeth to allow the water to clean thoroughly.
- Allow the water to flow into the sink.
- For Jet mode, press and hold the button to start cleaning, and release to stop.

Figure 9: The water flosser effectively targets plaque and food debris.
4. Maintenance
4.1 Cleaning the Water Tank
To prevent mold and residue buildup, clean the water tank regularly. Its wide-mouth, removable design makes this process simple:
- Detach the water tank from the main unit.
- Rinse the tank thoroughly with warm water.
- For deeper cleaning, use a soft brush and mild soap.
- Ensure the tank is completely dry before reattaching or storing to prevent bacterial growth.

Figure 10: The wide-mouth tank design facilitates easy cleaning and prevents residue.
4.2 Nozzle Storage
The COSLUS C51 features an integrated nozzle storage compartment, allowing you to keep your tips organized, dry, and ready for use. After each use, rinse the nozzle and store it in the designated compartment.

Figure 11: Integrated nozzle storage for convenience and hygiene.
5. Troubleshooting
If you encounter any issues with your COSLUS C51, please refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Device does not turn on. | Low battery or not charged. | Ensure the device is fully charged. Connect to a power source and allow sufficient charging time. |
| Weak water pressure. | Low battery, clogged nozzle, or incorrect mode/pressure setting. | Charge the device. Clean the nozzle. Select a higher pressure setting or a different mode. |
| Water leaks from the device. | Water tank not properly attached or damaged O-ring. | Ensure the water tank is securely fastened. Check the O-ring for damage and replace if necessary. |
| No water comes out. | Empty water tank or clogged intake. | Refill the water tank. Check for any blockages in the water intake tube. |
If the problem persists, please contact COSLUS customer support for assistance.
6. Specifications
| Feature | Detail |
|---|---|
| Model Number | C51 |
| Dimensions | 8.2 x 6.8 x 21.6 cm |
| Weight | 270 g |
| Water Tank Capacity | 300 ml |
| Pressure Range | 30-140 PSI |
| Pulse Rate | 1400-1800 pulses/minute |
| Modes | Clean, Orthodontic, Jet (3 modes, 6 settings each) |
| Waterproof Rating | IPX7 |
| Battery Life | Up to 30 days on a single charge (2-hour charge time) |
| Material | Acrylonitrile Butadiene Styrene (ABS) |
| Certifications | CE, FCC, RoHS |
7. Warranty and Support
COSLUS products are manufactured to high-quality standards. For any warranty claims or technical support, please contact COSLUS customer service through the retailer where the product was purchased or visit the official COSLUS website.
Please retain your proof of purchase for warranty purposes.
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