I bought these Born Free bottles and nipples, switching away from Avent, mainly b/c of they are bpa-free. The Born Free bottles and nipples are so diappointing in every way. First of all, they are harder to clean (extra 2 piece valve). The bottles leak from the screw on neck. The nipples collapse consistently. Nothing could be more frustrating than dealing with these product issues when you have a hungry baby to feed. Finally, I switched back to the Avent nipples which work on these bottles. If you do buy this product, DON'T invest in the nipples- just use Avent nipples. I am sorry I invested so much $$ in this system..and would just like to warn others on the disappinting performance.