Compare Britax Marathon Booster Car Seat - Onyx to Britax Boulevard Booster Car Seat - Shannon

The legendary Britax Marathon™ convertible car seat is renowned for safety, comfort, and convenience. The Marathon is also one of many Britax products renowned for its ability to keep your child in a harnessed restraint up to 65 pounds. Less

The Boulevard™ convertible car seat is the crown jewel in the Britax line of 'True Side Impact Protection'™ restraints. The deep side wings with EPS foam are engineered and tested for optimum side impact protection and adjust effortlessly with the turn of a knob to grow with your child…without removing the seat from your vehicle! The Britax-famous features of built-in lock-offs, 5-point harness with front adjuster, tangle-free webbing, push button release LATCH system with patented Versa-Tether®, and sculpted base ensures an easy installation with a secure fit. Comfort abounds with a plush, washable cover, while additional comfort foam, patented HUGS® system, shoulder belt comfort pads, integrated toddler pillow, and a removable infant body pillow provide a perfect, adjustable fit as your child grows from 5 to 65 pounds. Less