All the SuitCases (but no Basic SuitCase) are prepared for these straps, which you can store in one of the pockets. In seconds, you can attach the straps to the hard back and to the wheels (protecting your clothes from dirt at the same time).Without removing the ViolinCase and the BowCase you can cary the suitcase on your back; perfect when you travel with another big luggage, or there’s a lot of snow around.