Superior Electric S100 Replacement Carbon Brush Set. This carbon brush set replaces Skil 23973 & Bosch 2610023973. Made from Japanese Toyo TANSO Carbon. Carbon Brushes are normally referred to as wear items and commonly replaced due to friction during daily use in motors. Superior Electric carbon brushes are made to last longer. These carbon brushes make sure your motor runs properly, and fix a motor that operates intermittently.