Britax Römer Kidfix III M Cosmos Black

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Britax RomerSKU: 2000030985

£129 £170
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Available for immediate dispatch

Britax Römer Kidfix III M

Extending the widely popular Kidfix range, the new Britax Römer Kidfix III M highback booster in Cosmos Black features a longer seating area designed to accommodate children of all sizes, from small to tall, and is recommended for children aged between approximately 3.5 to 12 years of age (15 - 36 kg). Boasting all the usual safety features you would expect from Britax, including SICT and SecureGuard, the Kidfix III M is a great follow-on car seat to see your little one all the way through to 12 years of age. 

Ergonomic Seating

Providing unbeatable comfort even for tall children, Britax have extended the seating area of the Kidfix III M by roughly 20%, with an improved shape and extra-soft padding that provides optimum comfort and positioning even on long journeys. 


As the Kidfix III M uses the vehicle's 3-point seat belt instead of a harness, Britax Römer have included SecureGuard, which sits in the centre of the seat around the abdomen and provides a 4th contact point between your child and the seat belt. Keeping that extra contact point across the pelvic bones helps to reduce abdominal force by up to 35%* in the event of a frontal collision, whilst still allowing for some movement during travel. 

*Data collected during Britax Römer internal tests with Q6 dummy, representing an average 6-year-old child. 

SICT Side Impact Protection

SICT (Side Impact Cushion Technology) acts as a barrier between the car seat and the car's exterior, reducing impact force and absorbing energy before it reaches your child in the event of a side-on collision. Simply pop the SICT out from the seat on the side closest to the door to provide your little one with additional protection should you find yourself in an accident. 

Adjustable Headrest

The ergonomic headrest on the Kidfix III M is designed to help support your child's head if they fall asleep on long journeys, and can be adjusted to multiple height positions with just one hand, even when your child is in their seat. This helps to accommodate their changing needs as they grow and ensures the headrest is always in the best possible position; just above their shoulders. 

V-Shaped Backrest

The V-shaped backrest on the Kidfix III M is designed to provide optimum support for your child as they grow, ensuring plenty of space for their back and shoulders. The backrest also adjusts to suit the angle of your vehicle's seat, allowing for a better fit and more comfortable positioning for your child. 

Highback Booster Protection

The protection offered by the Kidfix III M highback booster is threefold: the shell itself provides complete protection from head to hip, which is especially useful in side-impact collisions; the upper and lower belt guides help to hold the seat belt in the safest position, and the extra padded headrest protects your child's head and neck whilst adding an additional level of comfort for long rides or on-the-road naps. 

Easy Clean-Up

The removable, machine washable seat cover is great for messy kids, spills, and accidents. Simply pop the cover off and stick it in the washing machine to make cleaning up super quick and easy. 

The Britax Römer Kidfix III M is the perfect choice for families looking to replace their infant car seat with a super protective, ultra-comfortable highback booster that will last right the way through from toddlerhood to pre-teen. 

The Kidfix Collection features a wide variety of amazing car seats by Britax Römer, click here to view the full range of Kidfix car seats from Britax Römer. 

Key Features

  • Group 2/3
  • SecureGuard technology
  • Superior Side Impact Protection (SICT)
  • Ergonomically optimised seat 
  • ISOFIX or belted installation
  • Removable padded cover
  • Adjustable V-shaped backrest grows with child
  • Height-adjustable ergonomically designed headrest
  • Intuitively position seat belt guides over shoulders & pelvis


Age suitability: from 4 to 12 years
Weight suitability: from 15kg to 36kg
Group: 2/3
Installation: Forward Facing, ISOFIX/3-point seat belt

Dimensions: 67cm - 85cm x 54cm x 43cm



Weight: 7.5kg 

If you place an order by 12pm between Monday to Friday of an item marked as available for immediate dispatch we will ensure the order is dispatched the same day.  Orders received after that time will be dispatched the following working day.  
Availability denotes the length of time the item will take to be available to dispatch. 
Shipping denotes the duration of time that an items takes to reach its destination the either our warehouse or manufacturer's warehouse.  For example an item with "Available in 7-10 working days" and "Standard Delivery" should be expected in 9-12 working days.  Please note working days excludes weekends and bank holidays. 

Our secure website and payment gateways perform a number of security checks against an order.  Any errors on the order could result in delays while we attempt to contact you to clarify any inaccuracies.  At Baby & Co we use a number of carrier services to ensure prompt and speedy delivery, this may include using more than one carrier for an order, however this is rare.
Your order may be dispatched from more than one location including our warehouse or directly from the manufacturer this may result in your order arriving on more than one consignment.  Aside from made to order items and direct delivery we offer the following delivery options. 

With the exception of made to order items and products sent directly by the supplier below you will find our standard delivery terms.  Please note that we only ship within the United Kingdom. 

Please note the following brands only deliver to UK mainland post codes, excluding some Scottish post codes:- Ickle Bubba, Boori, East Coast, Tutti Bambini, Mamas & Papas, Silver Cross furniture.

Please note that some nursery furniture deliveries will be to the customer's door, this may exclude internal apartment doors.

Standard Delivery
Region Rate Delivery Schedule
U.K. mainland Orders over £49.99 - Free
Orders £49.99 or under - £4.95
2-3 working days
Scottish Highlands £18 per order
U.K. Islands
& Isle Of Wight
£18 per order
Northern Ireland £9.99 per order*
Please note - our carriers only work Monday to Fridays (8am - 6pm). We regret our carriers cannot deliver at a specific time. ALL deliveries must be signed for.


Express Delivery
Region Rate Delivery Schedule
U.K. mainland Orders over £49.99 - £7.95
Orders £49.99 or under - £9.99
1-2 working days
Scottish Highlands £18 per order
U.K. Islands &
Isle Of Wight
£18 per order
Northern Ireland Not available *
Please note - our carriers only work Monday to Fridays (8am - 6pm). We regret our carriers cannot deliver at a specific time. ALL deliveries must be signed for.


*Please note there may be some delays shipping goods to Northern Ireland.

All returns are processed through the retailer and not the manufacturer; please contact us regarding any after sales issues. We endeavor to offer an impartial returns procedure for the benefit of all parties. To enable us to process your claim as efficiently as possible please follow this procedure, failure to follow this procedure could result in delays in processing your claim or return. 

In the first instance contact our returns department on or write to us with the following information:

  • Order Number
  • Name (Person who placed the order)
  • Contact telephone number.
  • Date of Purchase
  • Faulty Item (Product description)
  • Details of Fault (Description of fault)
  • If possible digital photos could also be sent to help identify the problem.

We will then, depending on the issue, either contact you to discuss the matter further or issue you with a returns authorisation number. Please note returns sent back without a returns number may be refused or could result in delays in processing.

If it is felt that the goods need to be returned for inspection you will need to do the following.

  • Box the item ready for collection. It is wise to retain the original packaging for this purpose. Our shipping company will not collect items which are not properly packaged
  • Contact us at to arrange collection. Please book your collection at least 2 days in advance and between Monday – Friday. Collections are usually made during the afternoon via Parcel Force. Please allow at least a 4 hour window when you will be available. If a collection is scheduled and you are not home as arranged you will be charged a £8.00 for the aborted collection
  • Please include your Returns Authorisation Number (RAN), proof of purchase and a description of the fault.

If you are not satisfied with your purchase, please return unused and its original packaging with any tags still attached for an exchange or refund. We do not accept returns on personalised items or hygiene sensitive items including duvets and mattresses once they have been removed from their protective wrappers. This does not affect your statutory rights.

  • We will refund the full amount to the original payment method excluding any shipping costs
  • Credit/debit card refunds can take up to 10 working days to be processed by your bank, we are unable to expedite this process.
  • Returned orders remain the customer's responsibility until safely received by us. We recommend using a reliable carrier and insuring the parcel for loss or damage. Alternately you can take advantage of our carrier service please contact us for a quotation.
  • Replacements, refunds or exchanges of damaged or incorrectly ordered items will not be processed until the original items are received and inspected.
  • If goods form part of a bundle then the whole order will need to be returned or the remaining items will revert to their normal recommended retail price and you will be refunded accordingly.
  • We reserve the right to refuse a refund if the condition of the goods are subject to normal wear and tear, misuse or damage.

Please note we are unable to offer a loan or replacement product while your return is being inspected or repaired. Proof of purchase must accompany any warranty claim. Most nursery items come with a 6 months guarantee; however some products have longer warranty periods, please check your warranty book for more details. This does not affect your statutory rights. If a fault develops within the guarantee period, we will arrange collection and inspection in our workshop. If the failure is confirmed to be due to a manufacturing fault we will arrange repair, or replacement if the repair in uneconomical.
If the fault is due to fair wear and tear, damage or misuse we will quote for a rectification and you will also be liable for the carriage charges, which are currently £18 per parcel*.
In the event of a dispute as to the cause of the failure the product will be sent to the manufacturer who will establish if the fault is covered by the manufacturer’s warranty. 
In the event the manufacturer identifies the fault is due to fair wear and tear, damage or misuse you will be liable for all carriage costs and any repair costs if you wish the product to be repaired.
Our workshop will be happy to quote for any non-warranty repair. All returned product must be carefully packed in cardboard. It is wise to retain original cartons for this purpose. If a collection is scheduled and you are not home as arranged you will be charged £8.00 for the aborted collection.
For furniture returns please read our terms and conditions page under the section Nursery Furniture Return Conditions.

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