The PetSafe sssCat Spray Cat Repeller is a fully automatic device for repelling cats from places you don't want them. The motion sensor detects your pet's arrival and the vial sprays out a spray to repel the cat. 100% safe for humans and animals, smell-free and also leaves no trace. It repels not only cats but other animals as well, so you can use it outdoors. The range of the spray is 1 meter and one pack will last you up to 500 sprays. You can set the cat repeller to a sound/spray programme or to a sound-only programme. For the first few days you can set the program to sound/spray and then you can change the program to sound only (the cat then expects the spray).