Although the term now refers to several other items including an electronic device intended for connecting computers to the internet, a router was originally only a woodworking tool. Router bits are pieces that go on the device and help to carve the wood or plastic into a correct shape. The shapes that are carved can be either for decorative purposes, or for assembly purposes.

Unlike mills which move more slowly but with greater power, routers move quickly and do not require a huge amount of power. This is the reason that the latter can be hand-held, while mills are almost always stationary and made of heavy materials such as iron. The high speed of routers can lead to burning of the material if the proper bit is not used and the proper care is not taken.

There are several types of routers, including table-mounted and hand-held varieties. Each has the ability to be fitted with several different jigs and bits, which allow the use of one tool in several different manners. A variety of different wood designs that are seen on the faces and edging of cabinets and furniture are done with specific router bits.

A jig is a tool that holds the wood and machine in position against each other. Jigs are essential for shaping complex designs, and for making sure symmetry is achieved. Different jigs can be combined with different bits in order to get a more complex design. Without a jig, it is easy for the design to be offset from where it should be, which can ruin the entire piece.

Routers come with at least one bit, and usually more. Additional ones can be purchased fairly easily, with the exception of specialty ones. Jigs are often purchased separately, and are chosen to be appropriate for the project in question. A jig that holds the device straight in order to make a line is different from one that will be used to carve an oval design on the wood. And the bits themselves come in a variety of sizes, as well as shapes, which are used to create artistic and practical images and cuts.

Using routers creates a large amount of fine dust. This dust is a respiratory hazard, so people should always wear a mask when they are routing. Eye protection is essential as well, in order to both keep out the dust and make sure that any accidental chips created from the material do not injure the person's eyes.