Yamaha Quality and Design Gold brass leadpipe Gold brass is extremely resistant to wear and corrosion and when used in a leadpipe it ensures long-time precision.Vertical valve tubing Traditionally, flugelhorns are made with vertical valve tubing.Monel pistons Monel pistons are resistant to corrosion and are an ideal choice for professional flugelhorn pistons which must retain precise precise fit and smooth action over many years.Hand-lapped pistons and slides Hand-lapped pistons and slides ensures an absolutely perfect fit and seal between the pistons and casing or slide parts. Such a perfect fit helps achieve smooth air flow and smooth action and improve the response and intonation of the instrument.Movable mouthpiece receiver Tuning is made easier with the movable mouthpiece receiver.Pressure formed tubing Perfectly rounded tubing results in less turbulence and a smoother airflow, thus allowing for an excellent scale and reduced resistance.Laser-fused pluzuma welded bell A high-energy laser fuses the brass together for a virtually seamless bell which allows continuous even vibrations.3rd valve trigger All 631G models include 3rd valve trigger for quick corrections in intonation.