lizzielou742 - I buy the one you saw (8 - 12 inches).
I have to snug it up quite a bit (the buckle ends up in the middle of my embroidered phone number) for Pepper. She is our smallest at 6 pounds.

I have to make it just a little smaller for Cammie -- She's 10 pounds and I have to set it to the max for Halo -- She's 13 pounds.

You might measure around Tito's neck. I think it will work for him. It works for our 3 who are all different sizes.