On a 1 cc syringe, it will have the numbers 10,20,30,40,50,60,70,80,90,100.
You'll want to fill the syringe (for the less than 9 pound kitties) to the 40 mark. The heavy weight cats will need to be at the 80 mark. Please do weigh them before you start this. They may weigh more or less than what you think they do.
Hope this will help the confusion a bit! Just holler at me if you need more help!