Features 1、Non ‑ core high frequency, clear and resounding, no ‑ core whistle design, strong whistle permeability , high frequency and high decibel can be achieved. 2、Double air chamber design, easy to blow, double air chamber professional referee trainer whistle, large volume, strong sound penetration. 3、Adjustable nylon hanger, hanger easily through the buckle, double ball fixed hanger length, there is unnecessary to afraid of losing and falling. 4、ABS resin material combined with macromolecule materials, non‑toxic and tasteless, healthy environmental protection. 5、The whistle original denture is extended to extend the service life. At the same time, it applies to basketball, football, volleyball and so on . Specification Item Type: Whistle Material: ABS Resin Weight: Approx.43g / 1.5oz Package List 1 x Whistle 1 x Lanyard 2 x Teeth Protection 1 x Clamp