Amazon has the Sentry Calming & Anxiety Reducing Dog Collar (5321) for $11.69 - 30% off (check “Save an extra” box, eligible on first S&S order for this product) - 5% off with Subscribe & Save (can cancel at any time) = $7.60 with free shipping on $25+ or with Prime (extra 15% off for 5+ S&S orders).

Reduces the fear of loud noises, such as thunderstorms and fireworks for up to 30 days.