Two cats that supposedly get on fine are very often just taking turns. They use the same windowsill at different hours, pass on the stairs without stopping, and the household reads that as harmony because nothing is being broken. The signs that it is not usually arrive somewhere else entirely — a patch of over-groomed fur, a scratched sofa arm, or a corner of the hall that starts getting marked.

Beaphar's answer here is a plug-in diffuser carrying two things rather than one. It contains a copy of the Feline Facial Pheromone, the signal a cat leaves on furniture it has decided is safe, and the Maternal Appeasing Pheromone, which Beaphar link specifically to bonding and harmony in households with more than one cat. The kit is the diffuser plus a refill, it can be plugged in anywhere in the house, and Beaphar say it runs for up to 30 days of continual use before it needs replacing.

• 48ML starter kit: diffuser and one refill
• Contains a copy of the Feline Facial Pheromone and the Maternal Appeasing Pheromone
• Beaphar say up to 30 days of continual use per refill
• Plugs into any room in the house
• Suitable for cats of all ages
• Aimed at meowing, scratching, furniture damage, urinary marking and excessive licking

Two things the box leaves out, and one thing a diffuser cannot fix. No room size is published anywhere in what Beaphar have supplied — nothing says how large an area one unit covers, or whether an open-plan house or a two-storey one needs a second, and a diffuser downstairs is doing very little for a cat that lives on a landing. It is also an ongoing cost rather than a one-off purchase, since continual use means a refill roughly monthly for as long as you keep it running. And a pheromone does not remove whatever the cat is reacting to: sudden marking, straining in the tray or a new bald patch are worth a vet's opinion before they are treated as behaviour, because pain and urinary problems look exactly like this from the outside.

Who it's for: homes where two or more cats share the space and the friction is quiet rather than loud, and anyone with a move, a new baby, a new animal or a building job coming that the cat has not agreed to.