Silkskin, by Silikids is a thick silicone cover that slips onto baby bottles to protect them from breakage. These bottle covers come in various colors and they're not just safe, they're trendy, too.
Nipples
Even if a baby was never breastfed, her mouth was made to fit a real, human mother's nipple. Many baby bottle makers try to create bottle nipples that are as close to the real thing as possible.
Most companies have a range of nipple types that fit all or most of their bottles. Choosing the right type of nipple for your baby is pretty easy if you follow some simple guidelines.
The main concern with "standard" nipples is that they're not shaped much like a breast nipple. This unnatural design encourages the baby to grasp the nipple with his lips rather than taking as much of into his mouth as possible. This is a particular problem if you're switching back and forth between the breast and the bottle.
A better choice is an orthodontic nipple. These are made with the baby's mouth shape in mind and are designed to more closely mimic the shape of a mother's nipple.
The Avent bottle/nipple system is one of the best choices if you want a nipple with a natural shape and function. Avent nipples are specially made with a wider design and appear "stubbier" than regular nipples. The bottles are made to match and have a similar look.