Introduction
The Osann Four 360 S iSize car seat is designed to provide optimal safety and comfort for your child from birth up to approximately 12 years of age (40 cm to 150 cm height). This manual provides essential information for the correct installation, operation, and maintenance of your car seat. Please read it thoroughly before first use and keep it for future reference.
Safety Information
The Osann Four 360 S iSize car seat complies with the R129 i-Size standard, ensuring high safety performance. Always prioritize your child's safety by following these guidelines:
- Rear-Facing Use: It is mandatory to use the car seat in a rear-facing position for children from 40 cm up to at least 15 months of age. It is highly recommended to keep your child rear-facing for as long as possible, up to 105 cm, as this offers superior protection in the event of a frontal collision.
- Forward-Facing Use: The car seat can be used in a forward-facing position for children from 76 cm (and after 15 months of age) up to 150 cm.
- Harness System: For children from 40 cm to 105 cm, always secure your child using the integrated 5-point harness system.
- Vehicle Seat Belt: For children from 100 cm to 150 cm, the 5-point harness must be removed, and the child secured using the vehicle's 3-point seat belt.
- Isofix Installation: Always ensure the Isofix connectors are correctly engaged and the Top Tether (if applicable for the height range) is securely fastened.
- Never leave your child unattended in the car seat.
- Do not use the car seat if it has been involved in an accident, even if there is no visible damage.
Setup and Installation
Proper installation is crucial for your child's safety. Follow these steps carefully.
1. Isofix and Top Tether Installation (40-105 cm)
- Extend the Isofix connectors from the car seat base.
- Align the Isofix connectors with the Isofix anchor points in your vehicle and push until they click securely into place. Check for green indicators to confirm correct engagement.
- Route the Top Tether strap over the back of the vehicle seat and attach it to the designated Top Tether anchor point in your vehicle. Tighten the strap until the indicator shows it is correctly tensioned.
- Push the car seat firmly against the vehicle seat back to ensure a snug fit.
2. Isofix Installation (100-150 cm)
When using the car seat for children from 100 cm to 150 cm, the Top Tether is no longer required. The car seat is secured using only the Isofix connectors, and the child is secured with the vehicle's 3-point seat belt.
- Extend the Isofix connectors and attach them to the vehicle's Isofix anchor points as described above.
- Ensure the car seat is firmly against the vehicle seat back.
3. 360° Swivel Function
The car seat features a 360° swivel function to facilitate placing and removing your child. To rotate the seat, locate the rotation lever (usually at the front of the base) and engage it while turning the seat to the desired position (rear-facing or forward-facing). Ensure the seat locks securely into place before driving.

4. Headrest and Harness Adjustment
The headrest and 5-point harness system are designed to adjust simultaneously with one hand, ensuring a perfect fit as your child grows.
- Headrest: To adjust the headrest height, locate the adjustment lever (usually at the top of the headrest or behind it). Squeeze the lever and slide the headrest up or down to one of the 12 available positions. Ensure the headrest is positioned so that the shoulder straps are at or just below your child's shoulders when rear-facing, and at or just above when forward-facing.
- Harness: The 5-point harness automatically adjusts with the headrest. Ensure the harness straps are snug against your child's body, with no slack, and the chest clip is at armpit level.


5. Recline Positions
The car seat offers multiple recline positions for comfort and safety.
- Rear-Facing (40-105 cm): Features one lying position specifically designed for newborns.
- Forward-Facing (76-150 cm): Offers 4 recline positions for older children.

Operating the Car Seat
This section details the usage of the car seat through different growth phases.
Usage Phases

- Phase 1: Rear-Facing (40 - 105 cm)
For infants and toddlers, the car seat must be installed rear-facing using Isofix and Top Tether. Secure the child with the integrated 5-point harness. Utilize the newborn insert for smaller babies to ensure proper positioning and comfort.
- Phase 2: Forward-Facing (76 - 105 cm)
Once your child is at least 76 cm tall and older than 15 months, the car seat can be rotated to a forward-facing position. Continue to use the Isofix and Top Tether installation, and secure the child with the 5-point harness.
- Phase 3: Booster (100 - 150 cm)
For older children from 100 cm to 150 cm, remove the 5-point harness system. The car seat is then used as a high-back booster, secured by Isofix (Top Tether is not required). The child is secured using the vehicle's 3-point seat belt. Ensure the vehicle seat belt is correctly routed through the designated guides on the car seat and lies flat across the child's shoulder and lap.
Maintenance
Regular cleaning and maintenance will prolong the life of your car seat and ensure hygiene.
Cleaning the Fabric Cover

- The fabric cover of the Osann Four 360 S iSize car seat is removable and washable.
- To remove the cover, carefully detach it from the seat shell, following the instructions in the detailed manual (not provided here).
- Wash the cover at 30°C on a delicate cycle. Do not tumble dry, bleach, or iron.
- Allow the cover to air dry completely before reattaching it to the car seat.
Cleaning the Harness and Plastic Parts
- Wipe plastic parts and the harness straps with a damp cloth and mild soap.
- Do not use harsh detergents or abrasive cleaners.
- Ensure all parts are dry before reassembling or using the car seat.
Troubleshooting
If you encounter any issues with your car seat, refer to these common solutions:
- Car seat feels loose after installation: Recheck that the Isofix connectors are fully engaged (green indicators visible) and the Top Tether (if applicable) is tightened correctly. Push the seat firmly into the vehicle seat.
- Harness straps are difficult to adjust or too tight/loose: Ensure no straps are twisted. Check that the headrest is at the correct height for your child. Press the harness release button (if applicable) to loosen, then pull the adjustment strap to tighten.
- Seat does not rotate: Ensure the rotation lever is fully engaged and the seat is not obstructed. The seat may only rotate when the recline position is set correctly.
- Buckle is difficult to fasten/unfasten: Check for any debris in the buckle mechanism. Clean if necessary.
If problems persist, consult the full product manual or contact customer support.
Specifications
| Feature | Specification |
|---|---|
| Brand | Osann |
| Model | Four 360 S iSize |
| Installation Type | ISOFIX |
| Harness Type | 5-point (removable for booster mode) |
| Product Dimensions (L x W x H) | 44 x 60 x 50 cm |
| Child Height Range | 40 cm to 150 cm |
| Rotation | 360 degrees |
| Headrest Adjustment | 12 positions, one-hand adjustable |
| Recline Positions | 1 for newborn (rear-facing), 4 for child (forward-facing) |
Warranty and Support
For warranty information, product registration, or customer support, please refer to the documentation included with your purchase or visit the official Osann website. Keep your proof of purchase for any warranty claims.