The range of services offered by a manufacturer or reseller to its customers after the purchase of a product includes various services such as installation, training, usage advice, servicing, maintenance, troubleshooting, repair, application of warranty terms, transmission of information, and the availability of a 24/7 telephone support service. These services may be designated by the abbreviations P (parts), MO (labor) and/or D (travel), which specify the scope and nature of the associated warranty.