"This report provides advice, tactics and information related to the use of TTWS [through-the-wall sensor] in operational settings. The information provides law enforcement individuals and organizations with a better understanding of the capabilities and limitations of available TTWS equipment. When put into practice, an agency can make the most of the technology and improve the outcome and safety of operational scenarios in which it is deployed. The best practices report focuses on the use of commercially available TTWS devices suitable for law enforcement or emergency response applications" (p. 1). Sections following an executive summary cover: introduction; commercially available equipment that are FCC certified; best practices and lessons learned-practice with the device and learn how to use it, think of TTWS as a tool that is not a substitute for tactical training, make multiple measurements at different places to establish more reliable situational awareness, and be aware that metal can block radar signals or confuse results; and frequently asked questions about TTWS operation.