The Fine Lemon Tandex Proxi brushes has a brush diameter of 3.5mm with a wire diameter of 0.7mm. They come 6 brushes to a pack. TANDEX PROXI is an interdental brush available in 6 different sizes. It is used in conjunction with the special PROXI metal handle. TANDEX's unique patented design ensures the metal tip of the handle is enclosed by the plastic head, thus avoiding the risk of trauma to hard and soft tissues in the mouth. The PROXI plastic head colours identify the brush sizes, which are the same as those of the Flexi interdental brushes. These brushes also fit the very popular Curaprox metal handles.