The Porter-Cable 43578PC is a 3/8 inch beading router bit. The bit is used for decorative period edging. The 43578PC router bit has a Pozi-Stop Shank which automatically locates the bit at the correct height in the collet. This makes switching between bits fast and easy. The Pozi-Stop Shank creates a strong and long lasting bit. The Porter-Cable 43578PC bit includes a Monster Carbide which is 40% thicker carbide than standard bits. This generates less friction and provides smoother cuts.