Military grade Thumper grenade.
The item id for Medium Grenade 1 in unturned is 8068. 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: 0.2
Amount: 1
Calibers: 1
Caliber_0: 600
Blueprints: 1
Blueprint_0_Type: Tool
Blueprint_0_Supplies: 3
Blueprint_0_Supply_0_ID: 72
Blueprint_0_Supply_0_Amount: 1
Blueprint_0_Supply_1_ID: 73
Blueprint_0_Supply_1_Amount: 1
Blueprint_0_Supply_2_ID: 254
Blueprint_0_Supply_2_Amount: 1
Blueprint_0_Level: 2
Blueprint_0_Skill: Craft
Blueprint_0_Build: 32
Asset_Bundle_Version: 2