These coats can be found on most Terriers and Schnauzers. This type of coat does shed some, but it's usually light during most of the year. It sheds heavily during the spring and fall, known as blowing coat. Wire coats are usually easy to maintain by brushing and hand stripping or plucking out the topcoat. These coats are very suitable for Terriers that tend to dig and run through the brambles, as the dense, harsh coat protects the dog's skin. You can clipper this type of coat, and you need to card out the undercoat routinely or you will lose the harsher texture and coloring of the topcoat.
If you want to keep the darker coloring of the harsh wire coat, you must hand strip or pluck out the topcoat hairs when they grow past the length you want. The new guard hair grows in the rich, dark color, and you will be carding out undercoat, so you have more wire and less fuzz. When showing dogs with a wiry coat, hand stripping is the only proper method of grooming. This coat doesn't usually mat if there is a lot of harsh coat, and if a few mats do form, you can remove them easily.
On most breeds, each hair follicle has one topcoat, or guard hair, and several undercoat hairs. If you routinely shave off the coat, the guard hairs can slip below the surface of the hair follicle and the softer undercoat hairs continue to grow and pack the hair follicle. This can lead to blackheads, bumps, and irritations due to impacted hair follicles. This is why it's important to card out the dead undercoat to leave space for that guard hair to grow in.