A typical airsoft gun is noticeably lighter than its "real steel" counterpart due to the use of aluminium alloy and plastic materials, though some have added weights in them for a more realistic feel. Japan has specific rules about producing airsoft guns with metal parts, while newer guns, especially those made in Taiwan and Mainland China, have both internal and external parts that are metallic. Smoke caps, as well as noise amplifiers, are available for certain airsoft guns to add realism.