Children under 2 years old must use a car seat that faces toward the back of the car until they weigh 40 pounds or more, or they are at least 40 inches tall. Below are agencies within Santa Clara County that can provide car seat installation information and teach you how to properly install a car seat.The Plumas County Public Health Agency Car Seat Program can issue a free car seat to eligible families. California State law mandates the use of car seats, which SV Hopper does not provide. Rent car seats from us with just a few clicks. Contact ; Please use the following option to contact us: Postal address: Klarna INC 800 N. High St, Ste. 400.