The horns them selfs are plastic but the clips that cover the horn mouthes are metal. They snap on with about an 1/4" gap from the mouth rim.Not sure what you are talking about. Are the horns metal or plastic?
Interesting. Anyway I have removed them though Im not sure its any louder. Thanks for the info.A few years back someone who sounded like they knew what they were talking about said federal regs specified a max level on factory horns and the clips kept the Tundra horn under the spec.
Either way your horn is louder and has a better sound without them.