Decently-sized military cargo backpack. +49 Slots
The item id for Kuwait Desert Rucksack in unturned is 5304. You can use this ID with the commands below to spawn the item, give it to a player or buy it on a modded economy server.
Useable: Clothing
Size_X: 2
Size_Y: 2
Size_Z: 0.6
Quality_Min: 100
Quality_Max: 100
Width: 7
Height: 7
Blueprints: 2
Blueprint_0_Type: Apparel
Blueprint_0_Supply_0_ID: 5304
Blueprint_0_Product: 66
Blueprint_0_Products: 5
Blueprint_0_Build: 32
Blueprint_1_Type: Repair
Blueprint_1_Supplies: 1
Blueprint_1_Supply_0_ID: 66
Blueprint_1_Supply_0_Amount: 5
Blueprint_1_Build: 32