Product Details

• Item Package Dimensions L x W x H: 3.66 x 2.68 x 0.98 inches
• Package Weight: 0.03 Kilograms
• Brand Name: JYWYBF
• Model Name: Ball-free Whistle
• Color: Black
• Material: Plastic
• Suggested Users: Men and Women's
• Number of Items: 3
• Manufacturer: JYWYBF
• Included Components: Whistle with Lanyard

• 【HIGH DECIBEL & HIGH PENETRATION】 The ball-free whistle design makes it possible to blow with less effort and produce a loud, high-pitched and penetrating sound even when using less force. This is especially important for occasions that require frequent use of whistles for teachers, such as physical education, outdoor adventures or emergency calls for help.
• 【EXCELLENT QUALITY & HIGH SAFETY】 The emergency whistles are made of high quality environmentally friendly non-toxic thickened plastic, while the ball-free design will not cause safety hazards during use due to accidentally swallowing or inhaling small parts inside the mouth. This is an important consideration for children, the elderly or special populations.
• 【DURABLE & EASY TO CLEAN】 The ball-free design means fewer parts and simpler construction, which reduces the possibility of failure and damage. This makes the ball-less whistles more durable in long-term use and able to withstand various environments and conditions. And the internal component-free design makes the whistle easy to clean when submerged in water.
• 【HUMANISED DESIGN】 Our whistles are equipped with a high quality thick lanyard, which not only frees up your hands when using the whistles, but also prevents them from getting lost. Meanwhile the lanyard and the bright colour of the whistle make it easy to be noticed in any scene when you wear referee whistle.
• 【SUPER COST-EFFECTIVE】You will get 3 loud whistles with high quality thick braid lanyard, very cost-effective.

How ball-free whistles work Ball-free whistles typically adopt a multi-chamber structure (e.g., a triple-chamber design). When airflow sequentially passes through multiple resonance chambers, sound waves repeatedly reflect and superimpose within the cavities, creating high-frequency resonance. Engineering Optimization of Ball-Free Whistles Design Simplified Mechanical Components: By eliminating traditional rolling beads, the whistle interior contains no moving parts. Airflow directly passes through fixed resonance chambers and vents, reducing energy loss or failure risks caused by ball jamming or rust.Geometric Design of Resonance Chambers: Triple-Chamber Layout: A series-connected chamber design extends airflow paths, amplifying sound wave superposition effects. Vent Angle Optimization: Sharp-angled vent edges enhance turbulence effects, improving vibration efficiency. Materials Optimization: High-strength ABS plastic ensures structural stability of chambers.