Children's Duffle, holdall bags called get and go by Stephen Joseph:

This beautiful duffle bag is made of durable and easy to clean vinyl material and makes a cute and stylish accessory, luggage for back to school or travel.
This room bag features a top zip, handles as well as adjustable and removable shoulder strap.
It measures : 48 cm length ( 19" ) x 26 cm ( 10") x  21 cm ( 8.5") deep.