Labelling is an essential part of any product or workplace and labels provide information, warn of potential hazards and can also indicate compliance with statutory requirements, such as CE testing or RoHS approval. On equipment, labels are used for serial and model identification numbers, as well as giving information about rating or end-of-life disposal. Cables can be identified by the use of alpha-numeric cable markers, and many other types of labels are available in various materials, such as paper and polyester, including self-laminating types. Custom labels can be produced using a label printer, with label tape rolls being widely available. Conspicuous labels are an important health and safety consideration and many hazard warning and prohibition signs can be obtained. Labels may also be used to show earth bonding points or ESD warnings. The use of labels is not restricted to walls and equipment, with floors often needing to be clearly marked. Floor labels typically delineate specific areas with lines and corner markings, or show directions in the form of arrows or sometimes footprints. Another important label used for electrical equipment is the type showing test dates. These are often marked by a punched hole and are regarded as being tamper-proof as they are destroyed if removed.