Britax Marathon 70-G3 Convertible Car Seat, Onyx
The Britax Marathon 70-G3 convertible car seat accommodates children rear facing from 5 to 40 pounds and forward facing from 20 up to 70 pounds. The Marathon 70-G3 is purposefully designed and engineered to minimize the forward movement of your child’s head during a frontal impact to reduce the risk of head injury with the
The Britax Marathon 70-G3 convertible car seat accommodates children rear facing from 5 to 40 pounds and forward facing from 20 up to 70 pounds. The Marathon 70-G3 is purposefully designed and engineered to minimize the forward movement of your child’s head during a frontal impact to reduce the risk of head injury with the following revolutionary Britax head safety technologies: base with safecell technology designed to compress in a crash, significantly lowering the center of gravity and counteracting the forward rotation of the child seat. Integrated steel bars strengthen the connection to the vehicle and reduce forward flexing of the child seat during a crash. Energy absorbing versa-tether features a two-point attachment and staged-release tether webbing to slow the forward movement and reduce the crash forces reaching the child. The Marathon 70-G3 also incorporates Britax side impact protection to contain the child and protect from the most severe types of crashes. The five-point harness is tangle-free with an fez-buckle system to retain the harness buckle in a forward position and harness holders that keep harness straps pulled to the sides to make boarding quick and hassle-free. Other features include a no-rethread harness and an easy-remove cover that also allows access to belt paths from the front of the seat, while the multiple buckle and recline positions, comfort pads, and infant body pillow provide premium comfort and positioning.
Packed with comfort and safety features, the BRITAX MARATHON 70-G3 Convertible Car Seat is designed with 360-degree protection to keep your child secure in the event of a crash. It offers high-density comfort foam for extra support, a cushiony cover, and an EZ-Buckle system for convenience when harnessing your child. The MARATHON 70-G3 accommodates children rear facing from 5 to 40 pounds and forward facing from 20 to 70 pounds.
Convertible Car Seat
(Onyx) At a Glance: Side Impact Protection system with energy-absorbing foam diverts crash forcesBase with SafeCell Technology compresses to counteract forward momentumEnergy-Absorbing Versa-Tether anchors seat and slows forward movementIntegrated steel bars reinforce seat stabilityTangle-free, no-rethread, five-point harness provides a secure fit Age/Weight Requirements:
5 to 40 pounds rear facing; 20 to 70 pounds forward facing
Limited one-year warranty
With the Side Impact Protection system, energy-absorbing foam helps divert crash forces. View larger.
SafeCell Technology helps to minimize the risk of head injury during a collision. View larger.
The EZ-Buckle System maintains the harness buckle in a forward position to prevent your child from sitting on it when boarding. View larger.
Side Impact Protection System Diverts Crash Forces
The BRITAX Side Impact Protection system includes a rigid shell with deep sidewalls lined with energy-absorbing EPP foam to contain your child’s head and body and divert crash force energy while creating a barrier against possible intruding objects. This system also protects your child’s head and chest.
SafeCell Technology for Advanced Protection
The base of the MARATHON 70-G3 includes SafeCell Technology comprised of SafeCells, an engineered material designed to compress in a crash. This compression lowers the center of gravity to counteract forward rotation of the seat, helping to minimize the risk of head injury during a collision.
Located in the sides of the seat shell, integrated steel bars strengthen the connection to the vehicle and prevent forward flexing of the seat during a crash to reduce the risk of head injury.
In the event of a sudden stop, the Energy-Absorbing Versa-Tether strap restricts forward movement and reduces crash forces with patented staged-release webbing and a 2-point attachment. This webbing securely anchors the top of your child seat to your vehicle in either rear- or forward-facing positions.
No-Rethread Harness System and Comfort Features
The tangle-free, five-point harness allows for multiple height positions and can be adjusted without dismantling the harness or removing the car seat from the vehicle. Two buckle positions provide a snug, comfortable fit as your child grows. The seat’s harness holders prevent the straps from getting in the way when you’re putting your child in the seat, while the EZ-Buckle system maintains the harness buckle in a forward position to prevent your child from sitting on it when first entering the seat. Rear- and forward-facing recline options, as well as high-density foam cushioning, help your child relax on the journey. And the plush cover comes with matching comfort pads and an infant body pillow to keep children of all ages comfortable and secure.
Easy Installation and Airplane-Approved Design
The MARATHON 70-G3 takes the guesswork out of installing your car seat thanks to a range of convenience features. An anti-slip, contoured base grips and protects the vehicle seat. Premium lower LATCH connectors make for a quick, simple, and tight installation, while the push-button allows you to easily uninstall the car seat. And easy-to-access built-in lock-offs provide a secure installation when using the vehicle lap and shoulder belt.
The MARATHON 70-G3 has a durable cover that can be removed for easy cleaning without uninstalling the car seat. It’s also approved for airplane travel.
Product and Warranty Information
The BRITAX MARATHON 70-G3 is made in the USA, has a seven-year life, and is backed by a manufacturer’s limited one-year warranty.
What’s in the Box
BRITAX MARATHON 70-G3 Convertible Car Seat, removable cover, comfort pads, infant body pillow, and user guide.
Click here to compare BRITAX car seats.
- Base with safecell technology designed to compress in a crash, significantly lowering the center of gravity and counteracting the forward rotation of the child seat which normally propels the child toward the front seat
- Integrated steel bars strengthen the connection to the vehicle and reduce forward flexing of the child seat during a crash
- Energy absorbing versa-tether features a staged-release tether webbing to slow the forward movement
- HUGS- Harness Ultra Guard System chest pads provides resistance to forward movement in the event of a crash
- Side impact protection comprised of deep side walls lined with energy-absorbing EPP foam distributes crash forces, shields from vehicle intrusion, and contains the head, neck and body