Check the listing for details. Cat Calming Pheromone Refill 6 Pack Drug Free Multi Cat Conflict Relief Solution. Condition: New. Listed at 73.39 USD. REDUCE & REUSE: Compatible with diffusers only. diffusers are reusable for up to 12 months; just replace the refill monthly for a continuous calming effect. MULTI-CAT CONFLICT: Use to help reduce multiple cat household tension and aggressive behaviors like swatting, scratching, biting, fighting, hissing, growling, spitting, screaming, non-playful staring, stalking, chasing, and blocking.