Check the listing for details. Topsum Cat Diffuser Kit Feline Calming Pheromone Kit 3 Diffusers. Condition: New, Made in China. Listed at 19.00 USD. The Topsum Cat Diffuser Kit is a set of three feline calming pheromone diffusers designed to help pets feel relaxed and comfortable in their environment. Made by the brand topsum in China, these diffusers are units that can be easily installed and used to provide a calming atmosphere for cats. Perfect for pet owners looking to create a calming and peaceful environment for their feline companions. New/Open Box. B3