HM009 is a high-quality heavy-duty universal mount that easily and securely attaches to headrests with 2-post configurations. Add a 4-Hole AMPS compatible tablet, mobile printer, or payment terminal (not included) to create the essential taxi mount. This headrest mount is best suited for viewing by one back seat passenger. Installation is easy. Attach the heavy-duty metal mount to the driver's side or passenger's side front seats using a socket wrench. The mounting plate measures 4.25 x 5.25 inches (108mm x 133mm), and features 4-Hole AMPS as well as other hole patterns to hold tablets, mobile printers, payment terminals, or other devices.