The closure mechanism on this hiking backpack is a zipper. This hiking backpack is made exclusively from synthetic material and it has a volume of 30 litres.
From Amazon
VAUDE Hiking Backpack Brenta, black 30l, Trekking Backpack for Women & Men, Comfortable Backpack Hiking with Integrated Rain Cover, Practical Compartment Layout
Trekkinn
Vaude Tents Brenta 30l Backpack Black
Hardloop
Vaude Brenta 30 - Hiking backpack Black 30 L