S.E. Shires developed the Model 4F in conjunction with Thomas Rolfs, Principal Trumpet of the Boston Symphony Orchestra. It features a special "4" bell taper with a slightly square bell bend, side seam, and French bead. These characteristics give its sound added complexity, cushion the blow slightly, and enhance its projection and power. The bell of the 4F is made with the traditional, longer bend to which many players are accustomed. For some players, this can open up the feel on top of the staff; for others, it improves the attack. Matched with a YEB leadpipe and W tuning slide, it produces an ideal balance of power, warmth, and brilliance. Nickel-silver balusters and valve caps add brilliance and character, increase its core, and contribute to cleanness and immediacy of attack.