Write down the various specifications writing concepts. A specification is a detailed description of a certain subject. A full description of all the workmanship and materials necessary to accomplish an engineering project in line with its drawings and specifications is contained in an engineering specification. This document serves as a guide for those who will carry out the work. The basic idea behind writing specifications is to create clear instructions that enable other people to understand what needs to be done and help them do it properly. Writing good specifications is important for two reasons: first, so that you don't end up with poor-quality work due to misunderstandings between the contractor and the client; second, so that you have something to go on when trying to obtain quotes from contractors interested in doing the work. There are several different approaches to specifying products and services. Some companies choose to use a single comprehensive document that covers everything that may need to be specified before they can start work. Others divide their attention between a standard contract or quotation that usually does not include specific details about individual items such as material quantities or delivery dates, and a series of additional documents used only when work needs to be assigned to specific parties involved in the project. Still others prefer to specify every detail at once using a variety of sources such as sketches, printouts from the Internet, and letters from clients or vendors.