When using the 98° Digital Bottle Warmer, proper alignment is key. Ensure a perfect fit with special adapters designed specifically for use with Playtex Ventaire bottles. These ring-shaped adapters are designed to connect the most popular baby bottle brands with ease. Just install the O-ring into the adapter and screw it onto the warming base. Then twist, flip and press to warm milk to body temperature (98.6 degrees F). Not too hot, not too cold -- the 98° Digital Bottle Warmer is always just right! And with this adapter, it's the perfect fit for baby's favorite bottle, too.