Civilian grade Masterkey shells.
The item id for Shells 2 in unturned is 381. 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.
Size_X: 1
Size_Y: 1
Size_Z: 0.25
Amount: 2
Count_Min: 2
Count_Max: 2
Calibers: 1
Caliber_0: 16
Pellets: 8
Tracer: 48
Blueprints: 1
Blueprint_0_Type: Ammo
Blueprint_0_Supplies: 1
Blueprint_0_Supply_0_ID: 381
Blueprint_0_Build: 30