Metal is a type of ammo only for the Engineer class that allows them to use metal to upgrade, repair, and refill their machinery. It costs 200 Metal to upgrade to another level, which is the maximum amount of metal an Engineer can hold. It costs 100 to make a Dispenser, 130 to make a Sentry Gun, and 125 (each exit and entrance) to make a Teleporter. With the Wrangler equipped, the Sentry Gun switches to a Mini-sentry gun which only costs 100 metal, allowing both dispenser and the gun to be built in one trip. However, a Mini-sentry gun CANNOT be upgraded, but refilling and repairing is an ability.