Table 1.

Bottle measurements for diameter, headspace, and milk-to-air interface

Delivery system	Diameter (mm)	Headspace (ml)	Milk-to-air interface (cm2)
Gerber (G)	52	176	21.23
Ventaire (V)	54	183	22.89
Dr. Brown's (DB)	50	66*	19.63
Elan (EL)	67	180	35.24*
BornFree (BF)	65	127*	33.17*
Playtex Drop-Ins (PD)	56	158	24.62*
Avent Natural (AN)	66	205	34.19*
Control	52	74*	20.42

*Statistically significant at p < 0.01