Drift softly down from the heavens.
The item id for Umbrella Black in unturned is 1103. 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: Cloud
Size_X: 2
Size_Y: 2
Size_Z: 0.7
Use_Auto_Icon_Measurements: false
Gravity: 0.25
Blueprints: 1
Blueprint_0_Type: Apparel
Blueprint_0_Supply_0_ID: 1103
Blueprint_0_Product: 66
Blueprint_0_Build: 32