The Standard Brush Set is best suited for Standard size or wide neck baby bottles. Will fit into Avent, Tomme Tippe or other brands alike in size. Neck opening should be at least 3 inches wide. Made of high density bristles that conform with more use. Outer brushes scrub the inside and outside of bottles. The middle brush is designed to fit into the crevices of the nipple tip. Strong suction at the bottom of the base to adhere to most sink types.