This is a set of round tip router bits with 1/4" shanks. The set contains 4 bits with ΒΌβ, 5/16β, 3/8β and Β½β round heads with ΒΌβ shanks. The bits are designed for CNC machines or small manual milling machines. Bits have 2 grooves and carbide tips. They are packed in individual plastic storage boxes. I find these bits work well on my CNC machine. They produce nice round rippled cuts with sharp edges. They are ideal for creating grooves on cutting boards. Tungsten Carbide can be a bit brittle but has a good cutting edge. Overall, it's a good choice for CNC machines.