The AMK Rescue Howler Whistle has an ultra light and compact design and the pea-less design works in any conditions - won't freeze or stick to your lips when cold. The special Triple - frequency sound cuts through surrounding noise. It is made from unbreakable ABS Plastic and is solid and durable. It is the smallest triple frequency whistle in existence. The AMK SOL Rescue Howler can be heard over 1 mile away and is 110 db audible, pea-less fail safe device. Each pack comes with two whistles which make it good value for these quality rescue items.