Can I use this booster seat without the back support?

Yes, on certain models, you can remove the back support to use the booster seat as a backless booster. To do this, lift the back support off the base by disengaging the U-shaped hooks on the bottom of the back support from the bars on the base. However, your child must still meet all the weight, height, and positioning requirements for backless use, which include weighing 40-100 lbs, being 40-57 inches tall, and having ears below the top of the vehicle seat cushion.