●The yellow tip is made of high quality brass, which is wear-resistant, rust-proof and durable ●The drill bit made of high speed steel 4241 is sharper and has a longer service life than conventional drill bits ●Widely used on wood and plastic, chips are automatically removed from these two side holes ●These hinge bits can reliably and accurately center the holes for mounting hinges and other types of hardware ●There are 5 mm and 1/4 inch drill bits that you can choose for drilling holes of different sizes