Specifications:Made of ABS material, these whistles are durable, non-odor and have good feeling to touch. These whistles make sounds by wind without needing battery or solar, which are also portable and convenient for you to use.They are designed to give off an unusual and effective sound which can be heard by animals but does no harm to human.The base has a switch, which can be detachable for cleaning.You can use them as animal alert whistles on cars, motorcycles, etc. Item Name: Alert WhistleMaterial: ABSFeatures: Portable, Practical, High quality, Easy to cleanSize: 5cm x 3.1cm x 1.85cm/1.97" x 1.22" x 0.73" (Approx.) Notes:Due to the light and screen setting difference, the items color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement. Package Includes:1 Pair of Alert Whistles