Metalite mouthpieces were designed by arnold brillhart and offer the brilliant sound qualities of metal using a durable composite material. metalite mouthpieces are free blowing and feature several facing options: nbsp; m5 - medium open (works best with medium reeds) m7 - open (works best with medium soft to medium reeds) m9 - most open (works best with soft to medium soft reeds) m9 available for tenor and baritone only.