Since I have 6 cats, I've been buying the largest size dog advantage which is the one for dogs over 55lbs. A vet that I used to take my cats to even suggested that I do this to help save me money because it has the same ingredients in it as the cat ones.

I either buy it online, at a pet store, or through a vet that's at a pet store because it's cheaper that way. I use small syringes and I put some tape on them at the right measurement because the numbers will eventully wear off. You could also use a permanent marker to do this.

I squirt the tube of advantage into a plastic test tube and then put a cap on it and I place it in a small glass so it's standing up. With 6 cats I don't even use one tube per month so I still have some left over. I do this every month year round and ever since I've been using advantage I've never had another flea problem.

For cats over 9lbs you need to measure .8ml and for cats under 9lbs you need to measure .4ml. You just separate their fur until you see their skin and then I squirt a little bit in several different places. I usually try to do it near their shoulder blades so that they can't try to lick it off. Sometimes I'll also do the back of their necks or heads too. You need to be quick because they hate the smell. Good luck.