Specifications: 3.74kHz and 4.10kHz mix the wavelengths, making the sound quality steely and penetrating. A unique dual chamber design that produces 2 different high waves. Made of ABS material, high strength, very durable for use. Portable size, easy to carry and use.Can be applied for basketball, football, volleyball, etc.Item name: Referee Whistle Material: ABS cord length: 85cm/33.46" (approx) Dimensions: 6cm x 2cm x 2.6cm/2.36" x 0.79" x 1.02" (Approx.) Notes: Due to the light and screen setting difference, the color of the item may be slightly different from the pictures. Measurement.Package includes: 1 x referee whistle, 1 x storage box (random color), 1 x mouth grip, 1 x finger grip, 1 x lanyard.