AR Resonance Top 25.10 60 Bronze Trombone; mouthpiece top for trombone; inner cup diameter: 25.10 mm; throat size: 6.0 mm (60); cup depth: Standard; comparable to Bach 6-3/4C, Schilke 47C4, Greg Black 7C Denis Wick 10CS; weight: L (light = standard); material: Bronze, silver plated; made in Italy