Keeping the same basic design of the hugely successful YTR-4335G, the new version offers some real improvements in terms of playability and a more powerful sound. The 4000 series now comes with a modified two-piece gold brass bell with a thickness of metal that has improved both sound and playability. Newly designed heavier valve caps and buttons give the trumpet more projection and power. Bb Trumpet, Bell: Gold brass, 123mm (4-7/8"), Bore: ML 11.65mm (0.459"), Finish: Gold lacquer, Weight: Medium, Mouthpiece: TR-11B4 Gold brass bell The newly redesigned, durable yet light two-piece bell is made of gold brass for a wide range of tone colors and to promote good technique and endurance. New piston, piston caps and buttons Highly durable monel alloy pistons as well as newly designed piston buttons and bottom caps help lengthen the life of the instrument while also maximizing sound quality. New tuning slides The 2nd and main tuning slides are produced using the same method as high-end models, which provides stability, a more refined tonal color and added durability. Brace Main tuning brace lets sound more focus and hold together.