What are the important safety warnings I should know about using this booster seat?

Never leave your child unattended and never leave an unsecured booster seat in your vehicle—it can be thrown around and cause injury. Replace the booster seat after any accident, as damage may not be visible. Do not modify the booster seat or use accessories from other manufacturers. Never use a booster seat with damaged or missing parts or a cut, frayed, or damaged vehicle seat belt. The booster seat can become very hot if left in the sun—always touch the surface before putting your child in it. Never use a second-hand booster seat whose history you do not know, and never use it without the armrests attached to the base or without the seat pad.