Bags such as this one are often very roomy. If you prefer black bags, then this should you just fine and it has a volume of 60 litres.
From Amazon
Osprey Europe Unisex Daylite Duffel 60 Black O/S
Trekkinn
Osprey Daylite Duffel 60l Black
This product is also available at 2 unverified merchants.