Evenflo has replaced thier cancer causing rubber nipples with clear silicone (YAY!) so if you are looking for slow flow nipples, you no longer need to buy seperate nipples. If you have gotton Evenflo bottles that did come with those brown rubber nipples, then replace the nipples (which contain cancer-causing nitrosamines) that come with them with clear silicone. Evenflo makes some (available below), but beware the fast flow as they have a big "X" opening that chokes most babies. Breast fed babies can use a slower flow nipple, as they are used to "working harder" for their milk. My daughter used the medium flow until she was done with bottles. Bottles come in 4 ounce or 8 ounce.
***Also just a note that THE VERY BEST THING you can do for your child's longterm health is to breastfeed whenever possible. For useful information click here.