I was a little unsure about this stuff but I am pleasantly surprised. Our 1.5 old Groodle had been marking his territory everywhere and I mean everywhere. 2.5meter long blinds were literally covered in wee, the carpets had old stains all over them! Nothing would stop him! In comes PetLab, smell is mostly gone, stains disappeared AND he’s stopped weeing in the same spots! In fact he’s stopped weeing inside as I’ve sprayed it pretty much everywhere! Some places needed extra attempts with the spray but this was months worth of marking his territory! I’m so impressed, I’ve just ordered 5L and will be giving the patio a go as well! Thank you Pet Lab!!!