Single Horn   452L F Single Children Horn 0.472" (11.99 mm) bore 11.9" (302 mm) bell Rose brass mouthpipe Mechanical link tapered rotary valves made of phosphorous hardened brass Adjustable thumb and little finger hooks Removable rotor levers for children or adults with short fingers Clear lacquered, nickel or silver plated finish Wood frame case Spec Chart 454L Bb Single Children Horn Model 452L with Bb key slides Spec Chart 752L F Single Horn 0.472" (11.99 mm) bore 11.9" (302 mm) bell Rose brass mouthpipe 3 mechanical link tapered rotary valves Nickel Silver outer tuning slides Clear lacquered, nickel or silver plated finish Wood frame case Spec Chart 754L Bb Single Horn Model 752L with 4 mechanical link tapered rotary valves and Bb key slid Spec Chart Single Horn Specification Single Horn Model No. Key Bore Size Bell Size Valves 452L F 0.472"(11.99 mm) 11.9"(302mm) 3 Rotor valves Adjustable rotor lever 454L Bb 0.472" (11.99 mm) 11.9"(302mm) 3 Rotor valves Adjustable rotor lever 752L F 0.472"(11.99 mm) 11.9"(302mm) 3 Rotor valves 754L Bb 0.472"(11.99 mm) 11.9"(302mm) 4 Rotor valves     452L 454L 752L 754L 852L 854L 952RL Alto Horn Baritone Horn Euphonium Tuba Marching Brass top