Comfort ZoneCat Calming Spray: Value Size (4 oz)

What is the difference between feliway classic and feliway comfortzone spray & scratch control? is one more concentrated than the other?

When I spray it on my furniture and touch my furniture will there be a nasty taste on my fingers?

Why does it say not to use in combination with a diffuser?

Why does this listing specifically say ‘do not use in combination with its diffusers’?? Does it create an interaction or overdose???