Three-in-one car seats give parents the flexibility to buy one car seat that serve their newborn until the child is old enough to ride without a safety seat. Cosco's 3-in-1 seat, the Alpha Omega, can be adjusted to accommodate a 5-pound newborn all the way through a 100-pound child without sacrificing safety.
Rear-Facing Infant Seat
A rear-facing infant is safest in the middle of the back seat. Car seats never should be installed in the front seat of a vehicle or in the jump seat in the back of a truck.
Place the child in the seat before installing it to adjust the straps properly. Straps should be at, or just below, the child's shoulders. If not, remove the child and adjust the straps by turning the seat over and sliding them out through the slots and moving them up or down to the proper position. Tighten the straps by lifting the lever on the base of the seat between the child's legs and tugging down on the strap. To loosen it, pull the lever up and then tug up on the shoulder harness.
Install the seat using either the LATCH system or seat belt. Position the seat so it faces the rear. Weave the LATCH or seat belt strap through the holes marked on the front of the seat. Fasten the seat belt or clip each end of the LATCH strap to the lower anchors of your backseat. These anchors may be labeled by the vehicle's manufacturer. Tighten the seat belt or strap by pulling on it until you can't get it any tighter. The seat should not wiggle more than an inch in any direction.
Strap the child into the seat by sliding his or her arms through the shoulder harness straps. Clip the button buckle into place between the child's legs. Snap together the chest clip and slide it up as high as possible.
This seat can be used until the child weighs 20 pounds or turns a year old. The seat, however, is designed to be used facing the rear until the child weighs 35 pounds, which gives the child more time to strengthen the neck muscles before traveling facing forward.
Forward Facing with Five-Point Harness
Remove the seat by unfastening the seat belt or LATCH system. To undo the LATCH strap, press the release button on the strap's adjustable side. On the other side, push the clip in and twist to free the LATCH clip from the seat anchor.
A child in a car seat that faces forward should have the shoulder harness straps even with, or above, his or her shoulders. Loosen or tighten the harness following the steps above.
When installing the seat to face forward, weave the seat belt or LATCH strap through the slots marked for the forward position. If your car has the LATCH system, attach the top tether strap on the car seat to the vehicle's tether clip. The location of the clip varies by vehicle.
The seat, when facing forward, is intended for children weighing up to 40 pounds and measuring 43 inches tall. When the child reaches either milestone, the seat can be used in its third way: a belt-positioning booster.
Remove the seat from the vehicle to take off its base. Use the recline lever to push the seat into a fully reclining position. Turn the seat over. There is a tab on the right and a bar on the left. While pressing the tab, slide the bar out. Tug the recline lever and the seat will lift off its base.
Turn the seat over to remove the harness straps so that the seat can be used with your vehicle's safety belt. Unhook the harness straps from the splitter plate at the front by pulling the top straps through the slots. Unhook the bottom straps from their buckle plates and slide them out of the seat.
Turn the seat over. There is a metal clip that holds a metal buckle in place. Turn it sideways and slide it through the slot to remove it from the seat.
Adjust the seat to its upright position. Place the child in the seat and use the safety belt to secure the child. Slide the chest strap through the slot on the side of the booster seat to keep the strap in a safe position. The lap belt should be across the child's legs and not up on his or her stomach. The booster seat now can be used until the child reaches your state's booster seat height and weight requirements.