Rail mounted iron sights.
The item id for Heatwave Iron Sights in unturned is 5004. 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: 0.125
Blueprints: 1
Blueprint_0_Type: Tool
Blueprint_0_Supplies: 1
Blueprint_0_Supply_0_ID: 5004
Blueprint_0_Product: 67
Blueprint_0_Products: 1
Blueprint_0_Build: 27