Description from the vendor website:

The same innovative Sleepypod mobile pet bed design, miniaturized. Secure kittens, puppies, or toy breeds in the versatile three-in-one mobile pet bed that's small enough to fit under an airline seat.

Use Sleepypod Mini as an everyday pet bed before transitioning to a carrier, car seat, or pet bed away from home. Many cats and dogs associate travel with negative experiences, such as a trip to the vet or kennel. Sleepypod Mini bed allows a pet to travel safely in the comfort of its own bed, reducing travel-related stress because it is already a trusted part of a pet's everyday life.

For added versatility, Sleepypod Mini can be used as a car seat. In the event of a collision or hard stop, Sleepypod's PPRS technology prevents a pet from being ejected while helping to reduce the damaging forces on the pet. Rigorous testing includes the same dynamic crash testing that ensures the performance of child safety restraints. It was tested at U.S., Canadian, and E.U. child safety standards. Independently tested and certified by the Center for Pet Safety for pets up to 7 pounds. Pets differ in size and shape, just like humans. Check Sleepypod's sizing guide for more information.