You close this bag with a zipper. You can carry it in several different ways, including a detachable shoulder strap.
From Quzo
Targus Geolite Essential. Case type: Messenger case Maximum screen size: 43.9 cm (17.3") Carrying handle(s) Shoulder strap. Weight: 500 g. Surface coloration: Monochromatic
Comet
Targus Geolite Essential 43.9 cm (17.3") Messenger case Black
Ebuyer
Targus Geolite 17.3" Slipcase