GUM Proxabrush Go-Betweens Refill -Tight, Tapered Interdental Brush, Box of 36 Brushes (2/Pk, 18 Pk/Box). Refill Brush Only. Replaceable heads for interproximal tooth cleaning, have bristles that incorporate a patented antibacterial agent for bristle protection. Removes up to 25% more plaque with new triangular bristles. Coated wire and antibacterial bristles on all sizes. Package of 36 brushes