ACME Silent Whistle No. 535 - The 'Silent' Dog Whistle for All Breeds | Also for Animal Training with Dolphins | For Humans (Almost) Not Audible

PRECISION SILENT DOG WHISTLE DESIGN: Emitting high-frequency ultrasonic waves clearly audible to dogs but almost silent to humans, the fully adjustable screw-sleeve lets you fine-tune the exact frequency to suit your dog's unique hearing range, regardless of breed, size, or temperament. ADJUSTABLE BRASS CONSTRUCTION: Precision-engineered in solid brass for premium weight, lifetime durability and a professional feel, this adjustable whistle features a screw piston mechanism for precise tuning across a wide frequency range, with special air directors supporting controlled sound output. CONTROLLED SOUND OUTPUT: Designed for structured training, this whistle delivers consistent sound cues with minimal effort across varied environments. Tunable to different frequencies to differentiate commands for multiple dogs, it fits naturally within any practical training kit. VERSATILE FOR EVERYDAY ROUTINES: This whistle integrates easily into daily routines alongside trusted dog walking accessories. Supplied with a booklet providing clear guidance on adjustment and training use, it supports handling as part of a practical set of dog essentials. Suitable for late-night garden training or urban areas where you want to avoid loud, piercing whistle blasts. UNRIVALLED PERFORMANCE, ICONIC DESIGN: Established in the 19th century, ACME has spent generations refining the art of sound signalling. Working dog whistles sit alongside professional, sporting, and safety applications, with every design reflecting depth of knowledge shaped through long-standing practice and continuous development across a broad range of uses.