https://www.cproducts.com/dr-catch-electronic-whistle-with-lanyard-adjustable-3-tone-high-volume-electric-whistle-for-referee-coaches-pe-teacher-outdoor-camping-hiking-and-boating-emergency-whistles-black
DR CATCH Electronic Whistle with Lanyard Adjustable, 3 Tone High Volume Electric Whistle for Referee Coaches, PE Teacher, Outdoor Camping Hiking and Boating Emergency Whistles (Black)