A Snug Lanyard Loop

My new brass whistle swung wildly in my hand as I wandered deeper into the alleyway. Tap, tap—I knocked it against a dented metal vaporator pipe to test its clang. Sturdy, but loose in my grasp! Wedged near the pipe's base sat a discarded black rubber gasket, ringed with three tiny notched teeth. I tilted my head, gave a rapid chirp, and tested its stretch between both palms. Supple and taut! I stretched the elastic ring wide and popped it straight over the whistle's tapered mouthpiece, snapping it into the narrow groove below the air slit. With a brisk tug, I hitched the whistle securely onto my bandolier strap. Solid lock!