If you have a little kid and you have to travel, you will understand the hassle of having to bring the carseat and the stroller, and if you are flying, you can't bring those things onboard, and you have to hold the baby most of the way. Since my wife's family is out of the country, she will often travel to visit her family a couple times a year, and we saw some other family having this, and made things a lot easier, we decided to get one ourselves.
The Sit n Stroll is fairly easy to operate, just hold a handle in the back and push, the wheel will come out and lock into place, and you can pull out the handle and it becomes a stroller, and do the reverse, the wheels will retract and hide under the seat. It will support up to 40 lbs, so I can still get several years of use out of it for my 20 month son. And it is FAA approved, so you can bring it on the flight without having to check in your carseat and stroller, and it will fit onto the standard coach airline seat, so we can use it like a carseat in a flght too! We also tried to use it as the carseat, and it will fit into most cars, and it is securely pretty well by the seat belt, I was worried that the shoulder strap will make the baby uncomfortable by passing too close to his face, but I found out that I can easily move the shoulder strap behind the carseat, so it won't pass over the baby at all.
The Sit n Stroll is pretty pricey at $250, and it claims you can take it out of the car and turn it into a stroller while the baby is still sleeping. Well, it is definitely not as easy as they claimed, my wife is not strong enough to pull out the wheel when our son is still in the seat, I am strong enough to do it now, but it will probably be too much when my son gain another 10 lbs. But all in all, this is a great product if you need to travel with a baby or small child a lot.
Sit'n'Stroll 5-n-1 is a combination car seat/stroller and conveniently transforms from seat to stroller in the push of a lever. Safety features include the 5-point harness, LATCH system, infant head bolster and 3 harness position. The seat offers a plush, padded, easy to wash cover and a convenient rear storage compartment. The product is FAA certified and can be used for children ages newborn to 4 years old (5 – 40 lbs.)
Easily converts to any of the 5 combinations:
Rear Facing Child Restraint (Up to 30 lbs)
Forward Facing Child Restraint (One year of age and 20 - 40 lbs.)